Cohabitation doesn't cause divorce after all

Want to avoid divorce? For years, the standard advice has been to wait to get married before moving in together, thanks to studies showing a link between premarital cohabitation and divorce.

This advice — which few Americans have followed — is on shaky ground. New research finds that premarital cohabitation isn't linked with divorce at all.

In a new briefing paper prepared for the Council on Contemporary Families, Arielle Kuperberg, a sociologist at the University of North Carolina, Greensboro, finds that when accounting for the age of moving in together, there is no difference in divorce rates between cohabiters and those who moved in after marriage.

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"Cohabitation does not cause divorce — yay," Kuperberg told Live Science, adding the exclamation because about two-thirds of new marriages in the United States start with cohabitation. [I Don't: 5 Myths About Marriage]

Moving in

While cohabitation is wildly popular, research dating back to the 1970s has suggested that non-legal relationships aren't as solidas those that come complete with wedding rings. Scientists have tried to explain the finding in multiple ways, suggesting that perhaps cohabiting couples slide into marriage for the wrong reasons and thus later divorce, or that cohabiters mentally keep their options open and don't lean on each other as strongly as married couples.

Kuperberg used data from the National Survey of Family Growth, a nationally representative survey carried out by the U.S. government. Using data from the 1995, 2002 and 2006 versions of the survey, she gathered information on more than 7,000 people who had been married at least once, including when they moved in together and when and if they divorced.

Previous studies compared the divorced rates of couples who cohabited with those who didn't by using the age of marriage. Kuperberg did something new: She compared the relationships using the date of first moving in together. That date, she reasoned, is when a couple really takes on the roles of marriage, regardless of whether they have a legal certificate.

Using this method, she found no link between whether people had cohabited before marriage and their rate of divorce. The turning point in age for picking a life partner seems to be about 23, Kuperberg said.

"That's when people are able to pick a partner who is more compatible," she said. "Maybe they are a little more mature. They're a little set up in the world."

The timing seems to coincide with college graduation, she added. Moving in with someone before both people are set in their career paths and schooling may increase the risk that one decides to take a job in New York while the other wants to go to graduate school in California.

Successful cohabitation

Other research included in the report finds that moving in may be fine, but rushing things might have disadvantages. Sharon Sassler, a sociologist at Cornell University, interviewed more than 150 cohabiters for a book she's working on about cohabitation in the United States. [5 Facts About Cohabiting Couples]

Sassler has found that most cohabiters with college degrees move in together only after a long stretch of dating. More than half have been couples for more than a year, with an average of 14 months dating before cohabiting. More than half of the cohabiters without college degrees move in together after less than six months of dating.

Financial need seems to push the less well-off into romantic roommate situations before they are ready, Sassler wrote in a commentary accompanying Kuperberg's new research.

"Knowing more about how relationships are formed and how they develop – such as how long couples are romantically involved before moving in together – may help us make better predictions about the chances that a relationship will dissolve, whether before the couple marries or after they do so," Sassler wrote.

Sassler's findings are interesting, said Stephanie Coontz, a historian at The Evergreen State University in Washington and director of public education at the Council on Contemporary Families. In the 1950s, the six-month "danger period" Sassler finds was, in fact, the norm. The average couple dated only six months before marrying, Coontz told Live Science.

Back then, though, marriage was more of a cookie-cutter proposition, Coontz said. Men had their roles (providing financially) and women had theirs (family care and domesticity). Now, marriage is individual and requires negotiation unique to each couple.

"You need much more maturity and negotiation skill," Coontz said.

The research is complicated by the fact that the people who cohabite and the people who don't are ever-changing. The first group of cohabiters in the 1960s were more highly educated than their peers and likely more conflict-prone, given their willingness to flout social convention, Kuperberg said. Today, the highest-educated people are the least likely to cohabit, likely because they face fewer financial pressures than the less-educated.

"We may be seeing a whole new dynamic developing," Coontz said. "That's the fun part of studying marriage and family right now. We're chasing a moving target."