In 2001, when I was 28, I broke up with my boyfriend. Allan and I had been together for three years, and there was no good reason to end things. He was (and remains) an exceptional person, intelligent, good-looking, loyal, kind. My friends, many of whom were married or in marriage-track relationships, were bewildered. I was bewildered. To account for my behaviour, all I had were two intangible yet undeniable convictions: something was missing; I wasn’t ready to settle down.

The period that followed was awful. I barely ate for sobbing all the time. (A friend who suffered my company a lot that summer sent me a birthday text this past July: “A decade ago you and I were reuniting, and you were crying a lot.”) I missed Allan desperately – his calm, sure voice; the sweetly fastidious way he folded his shirts. On good days, I felt secure that I’d done the right thing. Learning to be alone would make me a better person, and eventually a better partner. On bad days, I feared I would be alone forever. Had I made the biggest mistake of my life?

Ten years later, I occasionally ask myself the same question. Today I am 39, with too many ex-boyfriends to count and, I am told, two grim-seeming options to face down: either stay single or settle for a “good enough” mate. At this point, certainly, falling in love and getting married may be less a matter of choice than a stroke of wild great luck. A decade ago, luck didn’t even cross my mind. I’d been in love before, and I’d be in love again. This wasn’t hubris so much as naivety; I’d had serious, long-term boyfriends since my freshman year of high school, and simply couldn’t envision my life any differently.

Well, there was a lot I didn’t know 10 years ago. The decision to end a stable relationship for abstract rather than concrete reasons (“something was missing”), I see now, is in keeping with a post-Boomer ideology that values emotional fulfilment above all else. And the elevation of independence over coupling (“I wasn’t ready to settle down”) is a second-wave feminist idea I’d acquired from my mother, who had embraced it, in part, I suspect, to correct her own choices.

I was her first and only recruit, marching off to third grade in tiny green or blue T-shirts declaring: “A Woman Without A Man Is Like A Fish Without A Bicycle”, or: “A Woman’s Place Is In The House – And The Senate”. Once, in high school, driving home from a family vacation, my mother turned to my boyfriend and me cuddling in the backseat and said, “Isn’t it time you two started seeing other people?” She adored Brian – he was invited on family vacations! But my future was to be one of limitless possibilities, where getting married was something I’d do when I was ready, to a man who was in every way my equal, and she didn’t want me to get tied down just yet.

This unfettered future was the promise of my time and place. I spent many a golden afternoon at my small New England liberal-arts college debating with friends the merits of leg-shaving and whether or not we’d take our husband’s surname. (Even then, our concerns struck me as retro; hadn’t the women’s libbers tackled all this stuff already?) We took for granted that we’d spend our 20s finding ourselves, whatever that meant, and save marriage for after we’d finished graduate school and launched our careers, which of course would happen at the magical age of 30.

That we would marry, and that there would always be men we wanted to marry, we took on faith. How could we not? One of the many ways in which our lives differed from our mothers’ was in the variety of our interactions with the opposite sex. Men were our classmates and colleagues, our bosses and professors, as well as, in time, our students and employees and subordinates – an entire universe of prospective friends, boyfriends, friends with benefits, and even ex-boyfriends-turned-friends. In this brave new world, boundaries were fluid, and roles constantly changing.

In 1969, when my 25-year-old mother, a college-educated high-school teacher, married a handsome lawyer-to-be, most women her age were doing more or less the same thing. By the time she was in her mid-30s, she was raising two small children and struggling to find a satisfying career. What she’d envisioned for me was a future in which I made my own choices. I don’t think either of us could have predicted what happens when you multiply that sense of agency by an entire generation.

But what transpired next lay well beyond the powers of everybody’s imagination: as women have climbed ever higher, men have been falling behind. We’ve arrived at the top of the staircase, finally ready to start our lives, only to discover a cavernous room at the tail end of a party, most of the men gone already, some having never shown up – and those who remain are leering by the cheese table, or are, you know, the ones you don’t want to go out with.

In the 1990s, Stephanie Coontz, a social historian at Evergreen State College in Washington, noticed an uptick in questions from reporters and audiences asking if the institution of marriage was falling apart. She didn’t think it was, and was struck by how everyone believed in some mythical Golden Age of Marriage and saw mounting divorce rates as evidence of the dissolution of this halcyon past. She decided to write a book discrediting the notion and proving that the ways in which we think about and construct the legal union between a man and a woman have always been in flux.

What Coontz found was even more interesting than she’d originally expected. In her fascinating Marriage, a History: From Obedience to Intimacy, or How Love Conquered Marriage, she surveys 5,000 years of human habits, from our days as hunters and gatherers up until the present, showing our social arrangements to be more complex and varied than could ever seem possible. She’d long known that the Leave It To Beaver-style family model popular in the 1950s and 60s had been a flash in the pan, and like a lot of historians, she couldn’t understand how people had become so attached to an idea that had developed so late and been so short-lived.

For thousands of years, marriage had been a primarily economic and political contract between two people, negotiated and policed by their families, church and community. It took more than one person to make a farm or business thrive, and so a potential mate’s skills, resources, thrift and industriousness were valued as highly as personality and attractiveness. This held true for all classes. In the American colonies, wealthy merchants entrusted business matters to their landlocked wives while off at sea, just as sailors, vulnerable to the unpredictability of seasonal employment, relied on their wives’ steady income as domestics in elite households. Two-income families were the norm.

Not until the 18th century did labour begin to be divided along a sharp line: wage-earning for the men and unpaid maintenance of household and children for the women. Coontz notes that as recently as the late 17th century, women’s contributions to the family economy were openly recognised, and advice books urged husbands and wives to share domestic tasks. But as labour became separated, so did our spheres of experience – the marketplace versus the home – one founded on reason and action, the other on compassion and comfort. Not until the postwar gains of the 1950s, however, were a majority of American families able to actually afford living off a single breadwinner.

All of this was intriguing, for sure – but even more surprising to Coontz was the realisation that those alarmed reporters and audiences might be on to something. Coontz still didn’t think that marriage was falling apart, but she came to see that it was undergoing a transformation far more radical than anyone could have predicted, and that our current attitudes and arrangements are without precedent. “Today we are experiencing a historical revolution every bit as wrenching, far-reaching, and irreversible as the Industrial Revolution,” she wrote.

Last summer I called Coontz to talk to her about this revolution. “We are without a doubt in the midst of an extraordinary sea change,” she told me. “The transformation is momentous – immensely liberating and immensely scary. When it comes to what people actually want and expect from marriage and relationships, and how they organise their sexual and romantic lives, all the old ways have broken down.”

For starters, we keep putting marriage off. In 1960, the median age of first marriage in the US was 23 for men and 20 for women; today it is 28 and 26. Today, a smaller proportion of American women in their early 30s are married than at any other point since the 1950s, if not earlier. We’re also marrying less – with a significant degree of change taking place in just the past decade and a half. In 1997, 29% of my Generation X cohort was married; among today’s Millennials (those born in the late-70s to 90s) that figure has dropped to 22%. Compare that with 1960, when more than half of those aged 18 to 29 had already tied the knot. These numbers reflect major attitudinal shifts. According to the Pew Research Centre, a full 44% of Millennials and 43% of Gen Xers think that marriage is becoming obsolete.

Even more momentously, we no longer need husbands to have children, nor do we have to have children if we don’t want to. For those who want their own biological child, and haven’t found the right man, now is a good time to be alive. Biological parenthood in a nuclear family need not be the be-all and end-all of womanhood – and in fact it increasingly is not. Today 40% of children are born to single mothers. This isn’t to say all of these women preferred that route, but the fact that so many upper-middle-class women are choosing to travel it – and that gays and lesbians (married or single) and older women are also having children, via adoption or in vitro fertilisation – has helped shrink the stigma against single motherhood. Even as single motherhood is no longer a disgrace, motherhood itself is no longer compulsory. Since 1976, the percentage of women in their early 40s who have not given birth has nearly doubled. A childless single woman of a certain age is no longer automatically perceived as a barren spinster.

Of course, between the diminishing external pressure to have children and the common misperception that our biology is ours to control, some of us don’t deal with the matter in a timely fashion. Like me, for instance. Do I want children? My answer is: I don’t know. But somewhere along the way, I decided to not let my biology dictate my romantic life. If I find someone I really like being with, and if he and I decide we want a child together, and it’s too late for me to conceive naturally, I’ll consider whatever technological aid is currently available, or adopt (and if he’s not open to adoption, he’s not the kind of man I want to be with).

Foremost among the reasons for all these changes in family structure are the gains of the women’s movement. Over the past half century, women have steadily gained on – and are in some ways surpassing – men in education and employment. From 1970 (seven years after the Equal Pay Act was passed) to 2007, women’s earnings grew by 44%, compared with 6% for men. In 2008, women still earned just 77 cents to the male dollar – but that figure doesn’t account for the difference in hours worked, or the fact that women tend to choose lower-paying fields like nursing or education. A 2010 study of single, childless urban workers between the ages of 22 and 30 found that the women actually earned 8% more than the men. Women are also more likely than men to go to college: in 2010, 55% of all college graduates aged 25 to 29 were female.

By themselves, the cultural and technological advances that have made my stance on childbearing plausible would be enough to reshape our understanding of the modern family – but, unfortunately, they happen to be dovetailing with another set of developments that can be summed up as: the deterioration of the male condition. Of late, men have been rapidly declining – in income, in educational attainment, and in future employment prospects – relative to women. As of last year, women held 51.4% of all managerial and professional positions, up from 26% in 1980. Today women outnumber men not only in college but in graduate school; they earned 60% of all bachelor’s and master’s degrees awarded in 2010, and men are now more likely than women to hold only a high-school diploma.

No one has been hurt more by the arrival of the post-industrial economy than the stubbornly large pool of men without higher education. An analysis by Michael Greenstone, an economist at MIT, reveals that, after accounting for inflation, male median wages have fallen by 32% since their peak in 1973, once you account for the men who have stopped working altogether. The Great Recession accelerated this imbalance. Nearly three-quarters of the 7.5 million jobs lost in the depths of the recession were lost by men, making 2010 the first time in American history that women made up the majority of the workforce. Men have since then regained a small portion of the positions they’d lost – but they remain in a deep hole, and most of the jobs that are least likely ever to come back are in traditionally male-dominated sectors, like manufacturing and construction.

The implications are extraordinary. If, in all sectors of society, women are on the ascent, and if gender parity is actually within reach, this means that a marriage regime based on men’s overwhelming economic dominance may be passing into extinction. As long as women were denied the financial and educational opportunities of men, it encouraged them to “marry up” – how else would they improve their lot? Now that we can pursue our own status and security, and are therefore liberated from needing men the way we once did, we are free to like them more, or at least more idiosyncratically, which is how love ought to be, isn’t it? When Gloria Steinem said, in the 1970s, “We’re becoming the men we wanted to marry,” I doubt even she realised the prescience of her words.

But while the rise of women has been good for everyone, the decline of males has obviously been bad news for men – and bad news for marriage. For all the changes the institution has undergone, American women as a whole have never been confronted with such a radically shrinking pool of what are traditionally considered to be “marriageable” men – those who are better educated and earn more than they do. So women are now contending with what we might call the new scarcity. Even as women have seen their range of options broaden in recent years – for instance, expanding the kind of men it’s culturally acceptable to be with, and making it OK not to marry at all – the new scarcity disrupts what economists call the “marriage market” in a way that in fact narrows the available choices. This shrinking pool of traditionally “marriageable” men is dramatically changing our social landscape, and producing startling dynamics in the marriage market, in ways that aren’t immediately apparent.

In their 1983 book, Too Many Women? The Sex Ratio Question, two psychologists developed what has become known as the Guttentag-Secord theory, which holds that members of the gender in shorter supply are less dependent on their partners, because they have a greater number of alternative relationships available to them; that is, they have greater “dyadic power” than members of the sex in oversupply. How this plays out, however, varies drastically between genders.

In societies where men heavily outnumber women – in what’s known as a “high-sex-ratio society” – women are valued and treated with deference and respect and use their high dyadic power to create loving, committed bonds with their partners and raise families. Rates of illegitimacy and divorce are low. Women’s traditional roles as mothers and homemakers are held in high esteem. In such situations, however, men also use the power of their greater numbers to limit women’s economic and political strength, and female literacy and labour-force participation drop.

One might hope that in low-sex-ratio societies – where women outnumber men – women would have the social and sexual advantage. (After all, didn’t the mythical all-female nation of the Amazons capture men and keep them as their sex slaves?) But that’s not what happens: instead, when confronted with a surplus of women, men become promiscuous and unwilling to commit to a monogamous relationship. (Which, I suppose, might explain the Amazons’ need to keep men in slave quarters.) In societies with too many women, the theory holds, fewer people marry, and those who do marry do so later in life. Because men take advantage of the variety of potential partners available to them, women’s traditional roles are not valued, and because these women can’t rely on their partners to stick around, more turn to extrafamilial ambitions like education and career.

As a woman who spent her early 30s actively putting off marriage, I have had ample time to investigate, if you will, the prevailing attitudes of the high-status American urban male. (Granted, given my taste for brainy, creatively ambitious men – or “scrawny nerds,” as a high-school friend describes them – my sample is skewed.) My spotty anecdotal findings have revealed that, yes, in many cases, the more successful a man is (or thinks he is), the less interested he is in commitment.

Take the high-powered magazine editor who declared on our first date that he was going to spend his 30s playing the field. Or the prominent academic who announced on our fifth date that he couldn’t maintain a committed emotional relationship but was very interested in a physical one. Or the novelist who, after a month of hanging out, said he had to get back out there and tomcat around, but asked if we could keep having sex anyhow, or at least just one last time. Or the writer (yes, another one) who announced after six months together that he had to end things because he “couldn’t continue fending off all the sexual offers”. And those are just the honest ones.

To be sure, these men were the outliers – most of my personal experience has been with commitment-minded men with whom things just didn’t work out, for one reason or another. But the non-committers are out there in growing force. If dating and mating is in fact a marketplace – and of course it is – today we’re contending with a new “dating gap”, where marriage-minded women are increasingly confronted with either deadbeats or players.

When I turned 36, I’d been in the dating game for longer than I’d ever thought possible, and I wanted out. (Is there an expiry date on the fun, running-around period of being single captured so well by movies and television?) My escape came to me in the form of a revelation: all this time, I realised, I’d been regarding my single life as a temporary interlude, one I had to make the most of – or swiftly terminate, depending on my mood. Without intending to, by actively rejecting our pop-culture depictions of the single woman – you know the ones – I’d been terrorising myself with their spectres. But now that 35 had come and gone, all bets were off. It might never happen. Or maybe not until 42. Or 70, for that matter. Was that so bad? If I stopped seeing my present life as provisional, perhaps I’d be a little… happier. Perhaps I could actually get down to the business of what it means to be a real single woman.

It’s something a lot of people might want to consider, given that now, by choice or by circumstance, more and more of us (women and men), across the economic spectrum, are spending more years of our adult lives unmarried than ever before. The numbers are striking: The Census Bureau has reported that in 2010, the proportion of married households in America dropped to a record low of 48%; 50% of the adult population is single (compared with 33% in 1950) – and that portion is very likely to keep growing, given the variety of factors that contribute to it. The median age for getting married has been rising, and for those who are affluent and educated, that number climbs even higher. (Indeed, Stephanie Coontz told me that an educated white woman of 40 is more than twice as likely to marry in the next decade as a less educated woman of the same age.) Last year, nearly twice as many single women bought homes as did single men. And yet, what are our ideas about single people? Perverted misanthropes, crazy cat ladies, dating-obsessed shoe shoppers, etc – all of them some form of terribly lonely. The single woman is very rarely seen for who she is – whatever that might be – by others, or even by the single woman herself, so thoroughly do most of us internalise the stigmas that surround our status.

In 2005, social psychologist Bella DePaulo coined the word singlism, in an article she published in Psychological Inquiry. Intending a parallel with terms like racism and sexism, DePaulo says singlism is “the stigmatising of adults who are single [and] includes negative stereotyping of singles and discrimination against singles”. In her 2006 book, Singled Out, she argues that the complexities of modern life, and the fragility of the institution of marriage, have inspired an unprecedented glorification of coupling. (Laura Kipnis, the author of Against Love, has called this “the tyranny of two.”) This marriage myth – “matrimania”, DePaulo calls it – proclaims that the only route to happiness is finding and keeping one all-purpose, all-important partner who can meet our every emotional and social need. Those who don’t have this are pitied. Those who don’t want it are seen as threatening. Singlism, therefore, “serves to maintain cultural beliefs about marriage by derogating those whose lives challenge those beliefs”.

The cultural fixation on the couple blinds us to the full web of relationships that sustain us on a daily basis. We are far more than whom we are (or aren’t) married to: we are also friends, grandparents, colleagues, cousins, and so on. To ignore the depth and complexities of these networks is to limit the full range of our emotional experiences.

Personally, I’ve been wondering if we might be witnessing the rise of the aunt, based on the simple fact that my brother’s two small daughters have brought me emotional rewards I never could have anticipated. I have always been very close with my family, but welcoming my nieces into the world has reminded me anew of what a gift it is to care deeply, even helplessly, about another. There are many ways to know love in this world.

This is not to question romantic love itself. Rather, we could stand to examine the ways in which we think about love; and the changing face of marriage is giving us a chance to do this. “Love comes from the motor of the mind, the wanting part that craves that piece of chocolate, or a work promotion,” Helen Fisher, a biological anthropologist and perhaps this country’s leading scholar of love, told me. That we want is enduring; what we want changes as culture does.

Our cultural fixation on the couple is actually a relatively recent development. Though “pair-bonding” has been around for 3.5 million years, according to Helen Fisher, the hunters and gatherers evolved in egalitarian groups, with men and women sharing the labour equally. Both left the camp in the morning; both returned at day’s end with their bounty. Children were raised collaboratively. As a result, women and men were sexually and socially more or less equals; divorce (or its institution-of-marriage-preceding equivalent) was common. Indeed, Fisher sees the contemporary trend for marriage between equals as us “moving forward into deep history” – back to the social and sexual relationships of millions of years ago.

It wasn’t until we moved to farms, and became an agrarian economy centred on property, that the married couple became the central unit of production. As Stephanie Coontz explains, by the middle ages, the combination of the couple’s economic interdependence and the Catholic church’s success in limiting divorce had created the tradition of getting married to one person and staying that way until death do us part. It was in our personal and collective best interest that the marriage remain intact if we wanted to keep the farm afloat.

That said, being too emotionally attached to one’s spouse was discouraged; neighbours, family, and friends were valued just as highly in terms of practical and emotional support. But as the 19th century progressed, and especially with the sexualisation of marriage in the early 20th century, these older social ties were drastically devalued in order to strengthen the bond between the husband and wife – with contradictory results. As Coontz told me: “When a couple’s relationship is strong, a marriage can be more fulfilling than ever. But by overloading marriage with more demands than any one individual can possibly meet, we unduly strain it, and have fewer emotional systems to fall back on if the marriage falters.”

Some even believe that the pair bond, far from strengthening communities (which is both the prevailing view of social science and a central tenet of social conservatism), weakens them, the idea being that a married couple becomes too consumed with its own tiny nation of two to pay much heed to anyone else. In 2006, the sociologists Naomi Gerstel and Natalia Sarkisian published a paper concluding that unlike singles, married couples spend less time keeping in touch with and visiting their friends and extended family, and are less likely to provide them with emotional and practical support. They call these “greedy marriages”. I can see how couples today might be driven to form such isolated nations – it’s not easy in this age of dual-career families and hyper-parenting to keep the wheels turning, never mind having to maintain outside relationships as well. And yet we continue to rank this arrangement above all else!

Now that women are financially independent, and marriage is an option rather than a necessity, we are free to pursue what the British sociologist Anthony Giddens termed the “pure relationship”, in which intimacy is sought in and of itself and not solely for reproduction. (If I may quote the eminently quotable Gloria Steinem again: “I can’t mate in captivity.”) Certainly, in a world where women can create their own social standing, concepts like “marrying up” and “marrying down” evaporate – to the point where the importance of conventional criteria such as age and height, Coontz says, has fallen to an all-time low (no pun intended) in the United States.

Everywhere I turn, I see couples upending existing norms and power structures, whether it’s women choosing to be with much younger men, or men choosing to be with women more financially successful than they are (or both at once). My friend M, a successful film-maker, fell in love with her dog walker, a man 12 years her junior; they stayed together for three years, and are best friends today. As with many such relationships, I didn’t even know about their age difference until I became a member of their not-so-secret society. At a rooftop party last September, a man 11 years my junior asked me out for dinner; I didn’t take him seriously for one second – and then the next thing I knew, we were driving to his parents’ house for Christmas.

In the months leading to my breakup with Allan, my problem, as I saw it, lay in wanting two incompatible states of being – autonomy and intimacy – and this struck me as selfish and juvenile; part of growing up, I knew, was making trade-offs. I was too ashamed to confide in anyone, and as far as I could tell, mine was an alien predicament anyhow; apparently women everywhere wanted exactly what I possessed: a good man; a marriage-in-the-making; a “we”.

So I started searching out stories about those who had gone off-script with unconventional arrangements. In August, I flew to Amsterdam to visit an iconic medieval bastion of single-sex living. The Begijnhof was founded in the mid-12th century as a religious all-female collective devoted to taking care of the sick. The women were not nuns, but nor were they married, and they were free to cancel their vows and leave at any time. Over the ensuing centuries, very little has changed. Today the religious trappings are gone (though there is an active chapel on site), and to be accepted, an applicant must be female and between the ages of 30 and 65, and commit to living alone. The institution is beloved by the Dutch, and gaining entry isn’t easy. The waiting list is as long as the turnover is low.

I’d heard about the Begijnhof through a friend, who once knew an American woman who lived there, named Ellen. I contacted an old boyfriend who now lives in Amsterdam to see if he knew anything about it, and he put me in touch with an American friend who has lived there for 12 years: the very same Ellen.

The Begijnhof is big – 106 apartments in all – but even so, I nearly pedalled right past it on my rented bicycle, hidden as it is in plain sight: a walled enclosure in the middle of the city, set a metre lower than its surroundings. Throngs of tourists sped past toward the adjacent shopping district. In the wall is a heavy, rounded wooden door. I pulled it open and walked through.

Inside was an enchanted garden: a modest courtyard surrounded by classic Dutch houses of all different widths and heights. Roses and hydrangea lined walkways and peeked through gates. The sounds of the city were indiscernible. As I climbed the narrow, twisting stairs to Ellen’s sun-filled garret, she leaned over the railing in welcome – white hair cut in a bob, smiling red-painted lips. A writer and producer of avant-garde radio programmes, Ellen, 60, has a chic, minimal style that carries over into her little two-floor apartment. Neat and efficient in the way of a ship, the place has large windows overlooking the courtyard and rooftops below. To be there is like being held in a nest.

When an American woman gives you a tour of her house, she leads you through all the rooms. Instead, this expat showed me her favourite window views: from her desk, from her (single) bed, from her reading chair. As I perched for a moment in each spot, trying her life on for size, I thought about the years I’d spent struggling against the four walls of my apartment, and I wondered what my mother’s life would have been like had she lived and divorced my father. A room of one’s own, for each of us. A place where single women can live and thrive as themselves.

© 2011 The Atlantic Media Co. A longer version of this article first appeared in the Atlantic Magazine. Read the full version here. All rights reserved. Distributed by Tribune Media Services