WHEN researchers ask cohabitors these questions, partners often have different, unspoken — even unconscious — agendas. Women are more likely to view cohabitation as a step toward marriage, while men are more likely to see it as a way to test a relationship or postpone commitment, and this gender asymmetry is associated with negative interactions and lower levels of commitment even after the relationship progresses to marriage. One thing men and women do agree on, however, is that their standards for a live-in partner are lower than they are for a spouse.

Sliding into cohabitation wouldn’t be a problem if sliding out were as easy. But it isn’t. Too often, young adults enter into what they imagine will be low-cost, low-risk living situations only to find themselves unable to get out months, even years, later. It’s like signing up for a credit card with 0 percent interest. At the end of 12 months when the interest goes up to 23 percent you feel stuck because your balance is too high to pay off. In fact, cohabitation can be exactly like that. In behavioral economics, it’s called consumer lock-in…

Jennifer said she never really felt that her boyfriend was committed to her. “I felt like I was on this multiyear, never-ending audition to be his wife,” she said. “We had all this furniture. We had our dogs and all the same friends. It just made it really, really difficult to break up. Then it was like we got married because we were living together once we got into our 30s.”