June and Ernie met while on a college field trip to the desert. They dated, fell in love, had a couple of kids, and bought a house in Santa Rosa. Together, they remodeled it into a home—her doing most of the sawing, him designing the cabinets.

Still in their early 30s, he fashioned a backyard shed into a cavernous studio where he writes, records and produces music; she built a charmingly rustic bed out of antique doors. Like their parents, they had children young, in their early 20s. June works full-time; Ernie is there when the kids, aged nine and seven, come home from school. Each helps shuttle the kids to karate and to cook evening meals. By all accounts, they are an idyllic family, with a dog, a cat, a mortgage and strictly enforced bedtimes.

Except that June is not married to Ernie. Nor does she intend to be.

Fifty years ago, June and Ernie would have been the exception to the rule—societal outcasts with suspect morality. Today they are just another couple redefining what it means to be committed and building a relationship outside the traditional bounds of a white-picket marriage. According to a recent Pew Research Center Poll, people like June and Ernie are not alone. They found that in 2008, only 52 percent of American adults were married, down from 72 percent in 1960—not so surprising. Yet Pew also found that almost 40 percent of Americans believe that marriage is becoming obsolete.

Given that we're not talking about the latest gadget with the shelf life of a hamster, but a venerable institution, how on earth did we get here?

In 1957, when my mother was a child, 80 percent of Americans thought people who remained single were "sick, neurotic or immoral," according to Stephanie Coontz in her epic tome Marriage, a History. My mom, like most of her generation, married young (at 19) and had children not long after. By the time I was born, on the last day of 1978, that statistic had dropped to 25 percent, which helps to explain why at 19 I was backpacking Europe with my best friend and being seduced by the works of Kurt Vonnegut. Like many of my generation, my 20s were a time of radical self-discovery, miserable heartbreak and global traipsing. I emerged from this decade intact, in love and peacefully unconcerned with the idea of marriage.

So when, at a solstice taco party with dear friends, my boyfriend dropped to his knee and asked if I'd be his "baby forever," I was stunned. Yes—we had been living together for almost a year, madly in love for almost two. And yes—I wanted to have a couple of kids, age together, maybe even invest in a fuel-efficient sedan. I just never saw any reason to ask the government to sanction it.

After all, for most of its existence, the institution of marriage has had nothing to do with romantic love. As societies farmed and then settled, issues of property rights, inheritance and blood lines made marriage the answer to problematic questions. How do we pass along our wealth? How do we keep our well-bred daughter from mingling with the street sweeper's son? And, paramount in the earlier days of civilization, how do we expand our familial alliances into a more powerful tribe?

As Eat, Pray, Love author Elizabeth Gilbert points out in her new book about marriage, Committed, "This is why the Old Testament is such a family-centric, stranger-abhorring, genealogical extravaganza." When more powerful people (Romans! Babylonians!) are ever-ready to pounce, the Chosen people do well to stick together. But in our modern urbanism and isolationism, a woman widowed does not need to marry the brother of her spouse, as was customary for the Hebrews.

In fact, given that women are no longer economically dependent on men, marriage has lost its most powerful foothold. In 21st-century America, I do not need a husband in order to have financial prosperity, a career, a fulfilling sex life, a good reputation or even children.

And yet I knew I wanted to build a life with this man. Given our shared home and intimacy, I also realized we already were a family. And so we decided to write vows and exchange them on our front porch on a gloriously hot Saturday this past September. June and Ernie built us an altar with driftwood we foraged at the beach. I wore my mother's 1973 union-made wedding dress. Our loved ones sat in the front yard while random people honked their approving horns from Humboldt Street. Everyone, it seems, loves a wedding.

Many-Spendored Things

Yet as author and feminist Ariel Levy points out, "What follows a wedding is a marriage. And marriage is an institution, not a party." Increasingly, Americans are eschewing this institution for more flexible definitions of family and commitment. The Pew poll finds that multigenerational families, cohabitating and children born to unwed mothers alike are all on the rise.

Even though Ernie is open to it, June views a marriage license as an unnecessary piece of potentially heavy luggage. "I've come from a long line of happily unmarried couples that last," she says, "and married couples who end up divorced." To her, marriage redefines the family into an obligation, rather than a choice, which can lead to resentment and unhappiness. "We each stay in this family because we want to stay, not because we have to."

This notion of choice is also at the heart of polyamory, the practice of having committed sexual relationships with more than one person at a time. Sometimes referred to as "responsible non-monogamy," polyamory can manifest in as many ways as there are condom flavors; the most common occurs when two people practice an "open" relationship or marriage.

Contrary to popular mythology, polyamory is not simply a giant orgy. Though people do have sex outside the primary relationship, there are rules. As Jen Angel of Yes! Magazine points out, "It certainly is possible to 'cheat' in an open relationship—by going back on an agreement or lying."

"We have been conditioned to believe that marriage is the only way to form a partnership with integrity," says Barbara Daugherty, who, at 55, has been practicing polyamory for 30 years, "but there is so much more love available when you're poly." Though Daugherty's marriage did eventually end, after 10 years, she is open to marrying again. "I'd like a committed partnership with both a man and a woman," she tells me.

As a sex surrogate based in Sebastopol, Daugherty is a licensed professional trained to help people with their sexual concerns through both counseling and physical intimacy. Though she does engage in all manner of sexual activity with her clients, she remains strictly clinical—this means absolutely no exchange of bodily fluids, including saliva. "I've seen 40-year-old virgins, men who just want to learn how to slow down and married men who are unsatisfied in their sex lives and want to save their marriages," she says.

Saving the marriage by having sex with a hired helper? To many, the irony of this attempt smacks of prostitution. When I ask Daugherty, she calmly counters: "Seeing a prostitute is like going out to dinner; seeing a sex surrogate is like going to cooking school. You take those skills home with you and implement them in your daily life."

A Stronger Union?

When it comes to marriage, the law of evolution is unflinching: if you want to survive, you've got to adapt. Marriage has undergone radical changes, not just since the days of Queen Victoria's white-gowned affair (which redefined the wedding wardrobe for good), but even in just the last 50 years. It wasn't until 1967 that the Supreme Court finally overturned the anti-miscegenation laws that 13 years later would have criminalized my in-laws' marriage (he is white; she is black). Today, one in seven new marriages is interracial.

And despite the gains of the feminist movement, the "marital rape exemption" enshrined husbands' complete sexual control over their wives' bodies until it was overturned in 1984. Laws that now seem utterly repressive and archaic, in other words, have only recently become relics.

But nothing has caused more hullabaloo of late, nothing has forced our society to reexamine and redefine the role of marriage, than the federal law banning same-sex marriage.

People who oppose gay marriage often argue that the "sanctity" of the institution is being put in jeopardy. As Gilbert and plenty of others have pointed out, a rudimentary look at Christian history reveals that marriage never really was sacred. After all, not only did Jesus never marry, but he opposed the Hebrews' tribalism by preaching that God no longer had favorites. Everyone was chosen! This amounted to the breaking of family ties, not the building of them.

But if marriage, and by extension the nuclear family, is what strengthens society, then why would it be kept as an elite privilege? In Sonoma and Marin counties, the number of filed marriage licenses has remained steady even as the population has continued to rise—with the exception of 2008, when, thanks to California's brief legalization of same-sex marriages, the number spiked higher than it had in years. In June of that year, teacher and activist Bridget Hayes, who lives in Santa Rosa, seized the opportunity to marry her partner in order to "make a public declaration," she says, "of our commitment and love to friends and family."

Evidently, despite all that's changed, marriage remains the yardstick by which society measures and legitimizes relationships. For this reason, June asked to remain anonymous for this article. "Many people I work with assume I'm married," she admits, "and because it's more socially acceptable, because I do not want to jeopardize my job, I let them."

Even though the United States remains a relatively prudish nation, every professional I spoke to for this article believes that homosexuals should (and will) gain the right to a legally sanctioned marriage. As Santa Rosa-based couples' counselor Frances Fuchs points out, "Marriage itself may never become obsolete, but I do believe that many of the old rules for marriage are obsolete."

For Love or Money

We live in a culture in which progress equals success. We're constantly told to upgrade: cars, iPods. Why not partners? Maybe it's not gay marriage, but capitalism that poses the greatest threat to the institution.

After all, the Pew poll finds that of all the changes marriage has endured, "perhaps the most profound is the marriage differential that has opened between the rich and the poor." In 2008, the median household income of married adults was 41 percent higher than for single adults. Ironically, many of those people who are living together to save money are the same people who are waiting until they have enough money to get married. As Don Ross, MFT and money coach in Santa Rosa, argues, "Money is a symbol of value in our culture, so to enmesh finances is to show full commitment."

The financial benefits of a marriage license are well cited. Here again, June and Ernie challenge the stereotype. As the primary breadwinner, June has a job that provides insurance coverage for domestic partners. "And when it comes to taxes, I've figured out that if we file separately and each claim a kid, we wind up saving more money than if we filed as married," she tells me.

According to Pew, only 30 percent of people surveyed believe that financial stability is a good reason to get married. The best reason? Love. But as Gilbert points out, "Marriages based on love are, as it turns out, just as fragile as love itself." Here in the West, our outlook is fundamentally self-focused. We set goals for ourselves and value the pursuit of reckless, albeit soul-satisfying endeavors. Just as we are free to marry, so, too, are we free to unmarry.

So is our "me"-centered cultural milieu antithetical to marriage? Not necessarily. A recent study reported in the New York Times shows that marriages are happiest, and most sustainable, when each person uses the partnership to "accumulate knowledge and experiences, a process called 'self expansion.'" Dutch researcher Caryl Rusbult coined this in the term "Michelangelo effect," referring to the way that partners can "sculpt" each other into more actualized, inspired people.

Case in point: because of the influence and support of my husband, I now play piano, listen to the music of Leslie Hall and grow an obscene amount of garden greens. Thanks to me, he lives in a less cluttered environment, plays sweaty basketball and travels to places like Bulgaria and Cuba.

Though marriage has come far since the days of the dowry, its future remains uncertain. Interestingly, polls find that many of those who predict its impending obsolescence still want to get married. Whether or not they actually will, of course, is another story. "We can never reinstate marriage as the primary source of commitment and care-giving in the modern world," writes Stephanie Coontz. "For better or for worse, we must adjust our personal expectations and social support systems to this new reality."

As the old paradigm shifts—and as people continue to challenge rigid notions of sexuality, partnership, family and marriage—society becomes more tolerant, and as a result, more loving. And who can resist that kind of new reality?

Send a letter to the editor about this story.