Why aren’t you in an open relationship yet? Carla Bruni Sarkozy, wife of ex-French President Nicolas Sarkozy, famously "prefers polygamy and polyandry." Reveal magazine quoted Will Smith as saying that he and his wife Jada Pinkett-Smith allow each other extra-marital dalliances. Oprah did a segment on open marriages. All of this talk of free love is enough to make women who prefer old-fashioned monogamy feel a bit, well, old-fashioned. But if history can teach us anything, the open relationship bandwagon will come and go, which is a good thing because most women still benefit from and prefer monogamy. Both YourTango contributor Jenny Block and Village Voice columnist Tristan Taormino have written about open relationships. 

Why? Women still generally do more work in relationships than men do and openness requires even more diligence than a regular relationship; women are taught to care more about relationships and risk more for them than men, so non-monogamy raises the stakes more for us. And, despite today’s female open relationship proponents, it’s men who typically initiate and prefer non-monogamy. People yearn for variety, and now that we live longer than ever, it’s unrealistic to imagine a couple staying together for fifty years without a single affair.

RELATED: 5 Harsh Reasons Women Get Bored With Monogamy

Statistics show twenty percent of men and thirteen percent of women cheat on their spouses. But open relationships are not the solution, says Ayala Pines, psychologist and author of Romantic Jealousy, because jealousy and envy are just as hardwired as monogamy. Only a third of monogamous marriages survive cheating because of jealousy and a lingering sense of betrayal, says Pines. And the success rate for open relationships is not any better for similar reasons. "In my experience with open relationships," she says, "the couple goes back to monogamy or else to illicit affairs. Or, it ends in divorce."

Another reason why open relationships don't work in practice for a lot of women is because they're simply too time-consuming. Block is upfront about the work involved in juggling a husband and a girlfriend. An excerpt from her book on The Huffington Post, Life In An Open Marriage prompted one HuffPo commenter to say, "I'm exhausted just reading about all the 'work' and never-ending 'communication' about feelings, situations, jealousy, worry, etc. It all sounds like much more effort than it's worth (IMO)."

Likewise, Taormino's Opening Up: A Guide to Creating and Sustaining Open Relationships is an intimidating 300 pages, in which the kind of person who is successful at non-monogamy is described as someone committed to knowing themselves "on a deep level," a process she says might include "psychotherapy and counseling, reading, writing, journaling, blogging, attending workshops and peer support groups, meditation, and various spiritual practices." While the idea of openness may be appealing to some women, it's hard to imagine many of us finding the time to juggle a second relationship. Especially those of us with careers and children.

RELATED: My Husband And I Tried To Have An Open Marriage. It Epically Failed

Open relationships are being billed as the wave of the future, but they’ve gone in and out of style every few decades, never becoming more than a fringe movement. According to Susan Squire, author of I Don’t: A Contrarian History of Marriage, "There have been experiments of mate-swapping in the 19th century and again in the 70s and a few Utopian societies, but it never seems to stick. It doesn't work or only works for a short period. Then, history cycles, marriage cycles, and everything repeats itself." 

The last time open marriages (often known as polyandry, free love, friends with benefits, et al were in vogue was during the revolution of the late sixties and seventies. In 1972, the landmark book Open Marriage documented Nena and George O'Neill’s attempts to redefine marriage and open up their relationship to other partners. It was a runaway bestseller and, like today, promoted the impression that open marriages were the way of the future. By 1977, Nena O’Neill had published The Marriage Premise, which argued that fidelity was not such a bad thing after all.

Squire herself got caught up in what she calls "the five minutes of open relationships" in the seventies. In her first marriage, she says, "We did this thing where we had to tell each other but we could be with whoever we wanted. Did it work? No. I remember him calling me to tell me he was drinking with some woman, and saying 'I'm going to go sleep with some woman, do you mind?' Of course, I minded. When faced with that, I wasn't into it. And the reverse was true as well." Pines brings up another X factor of open relationships. Despite all the progress of feminism, she says "women are still socialized to care more about relationships and desire commitment more than men." Just consider the multi-billion dollar wedding industry and the success of happily-ever-after rom-coms and shows like Sex and the City.

RELATED: An Open Marriage Didn't Save Our Relationship — It Nearly Destroyed It

We are also more likely to devote our lives to children, family, and spouse. In short, the stakes are higher if there's to be an emotional fallout from an open relationship. In Woody Allen's ménage a trois flick Vicky Cristina Barcelona, Javier Bardem's character is flagrantly trying to bed three women. The women agree, but Vicky falls in love with him and is tormented. Christina agrees to merely be the extra "salt" in the relationship between Bardem and their jealous ex-wife Maria Elena. Bardem is unflappable. Everyone in the theater laughs knowingly — for Bardem, it's about being intimate. But the women always seem to have a little too much invested, a little too much to lose.

And this isn’t just the stuff of a Woody Allen fantasy. Men are typically the ones who initiate open relationships. According to a 2016 survey, 1 in 5 out of almost 9,000 single people say that they have been in an open relationship at least once in their lives. The gender gap is due partially to the intimate habits of gay men, who are more likely than women or straight men to be in non-monogamous arrangements. But, it's also that "men tend to prefer open relationships more than women do," says Pines, who has decades of clinical and research experience on the subject, "because their preference for casual intimacy far exceeds women’s."

It's intriguing that Block and Taormino, two of today's loudest advocates for open relationships, are women. Historically, it's been men who've advocated for polyandry and men who've benefited. "In the ancient world, men were never expected to be faithful," says Squire. Women were severely punished for extra-marital affairs primarily because it threatened patrilineal culture, where the paternity of a child would be in question if the woman strayed. In the last three or four centuries, the Lutheran marriage model of fidelity has become the standard, which has given women a more equal stake in {{ romantic }} partnerships.

Sure, some women can tinker with this arrangement and come out on top, but for many of us there's a sense that this is part of the battle of the sexes we're not winning. So if you're feeling like a fuddy-duddy for not wanting two lovers, remember this open relationship thing is a fad, and, as history has shown us, this too shall pass. While it may seem like non-monogamy is feminism's natural next step, the fact is that women largely prefer one partner, and we enjoy putting time and emotion into our primary relationship. There's not enough reason for us to change our ideas about what makes a satisfying love life, just to get on board with a time-consuming relationship model.

RELATED: The One Thing Your Monogamous Relationship Needs To Work

Elizabeth Cline is an expert in sustainability and labor rights in the fashion industry and a professor of Fashion Policy and Consumerism and Sustainability at Columbia University. Her publications have been showcased in Forbes, Sierra and Atmos Magazine, Vogue Business, Slate, Los Angeles Times, The Atlantic, The New Yorker, AMC.com, SundanceTV.com, The New Republic, The Nation, and more.