By Laura Tedesco
July 01, 2014

Before we got married, my husband and I signed up for what seemed like a pre-marital group therapy session-a day-long seminar on the secrets of a blissful union, complete with conflict-management exercises and sex tips. I felt like the star student in the room -after all, I was a sex editor -until our instructor started rattling off the perils of living together before saying "I do." Her evidence: a few decades-old studies showing that couples who cohabited before marriage were more likely to divorce. I discreetly glanced around the room, hoping to spot other people with the guilty expression I knew was smeared across my face.

My husband and I moved in together just three months before getting hitched. And, if you talk to the scientists who research cohabitation, we did it for the wrong reasons: I was tired of driving the twenty minutes to his place, my apartment building had bed bugs, and I'd save nearly a thousand bucks a month. In other words, we didn't do it because we couldn't bear to be separated for another 90 days.

What we did have going for us: We were already engaged. We weren't sharing an address as a way to test our relationship-which is, according to Scott Stanley, Ph.D., co-director of the University of Denver's Center for Marital and Family Studies-pretty much the worst reason to shack up. "The reason [for living together] is actually pretty important," he emphasizes. In a 2009 study, his team found that people who moved in together as a "trial marriage" tended to have poorer communication, lower levels of dedication, and less confidence in the strength of their bond.

One particularly sticky spot: When you move in together-and you're not already on the road to marriage-you're simultaneously figuring out who has to clean the toilets and how to divide your rent, while also deciding if you're in it for the long haul, says Stanley. Traditionally, couples don't have to divvy up chores until they're hitched-but in this case, you're navigating two major hurdles at the same time, without the reassurance of a ring on your finger.

If living together isn't as blissful as expected, the obvious solution is to simply break up. Problem is, that's pretty tough to do. "Many people believe that living together beforehand can strengthen a marriage," says Anita Jose, Ph.D., a clinical psychologist at Montefiore Medical Center. "However, living together means people begin to share pets, mortgages, leases, and other practical things that make it harder to end a relationship that may have otherwise ended."

The all-too-common outcome? Unhappy couples remain under the same roof-and eventually, may even get married, only because it seems the appropriate thing to do after five years of living together. Stanley has a name for this phenomenon: "sliding versus deciding."

Despite these frightening findings, there is some recent research suggesting that living together isn't all bad-that some cohabiting couples fare just as well as those who don't share a bed until they say, "I do." An Australian study, published in the Journal of Marriage and Family, even found that living together before marriage reduces the risk of separation. One explanation: When the majority of non-married couples in a country opt to live together, the negative effects may start to disappear. "The argument is that cohabitation would have never been risky if it had always been accepted-that it's not living together that harms couples. It's the stigma of living together. People look down on them," says Stanley.

That said, he still thinks the struggles related to living together-or the lack thereof-boil down to commitment. "Cohabitation doesn't tell you anything about how committed the couple is," he says. "But if they're engaged or planning a future-it doesn't have to be marriage-that tells you a ton about the couple." In other words, if you've already figured out your future together, moving in together won't likely hurt your chances of a successful marriage. Studies consistently show that engaged couples who live together enjoy the same benefits-satisfaction, commitment, less conflict-as people who wait until marriage to move in.

So how can you make sure you're one of the cohabiters that eventually becomes happily hitched? "More than 50 percent of couples that move in don't talk about what it means," says Stanley. "You're together four nights a week, then five, and leave some extra clothes, a toothbrush, an iPhone charger. Then somebody's lease is up and all of a sudden you're living together. No discussion, no decision." Why that's dangerous: You may have totally different expectations, which can set you up for disappointment, says Jose. Before you sign a lease, candidly share what you think the move means: Do you see this as a step toward the altar-or just a way to save money? Then ask your guy to do the same. If you have totally opposite perspectives, reconsider sharing an address, says Stanley. And before taking the plunge, decide who does which chores and how you're going to handle your financial obligations, says Stanley. That awkward moment when the waiter brings your check? ("Do I pay half?") You'll experience that times ten when the first electric bill arrives-and you haven't already decided who's paying what.

As for me-a former cohabiter who did things halfway wrong, halfway right, in the eyes of the experts? One year and 112 days into marriage (yes, I'm counting), I can happily report that my husband and I didn't become one of the statistics we were warned about in our premarital class. We've survived, and even better, we've thrived. In fact, after the honeymoon, I found that we were able to just enjoy our new marriage, without having to figure out whose job it was to scoop the litter box (his, BTW). The kinks of our mutual existence were already sorted out, which left us only to relish our wedded bliss.