According to a recent headline in the Washington Post, “Living together is basically the same as marriage, study finds.” Is that true? I do not think so, but it is worth grappling with the study and related findings. The article is based on a study by Sara Mernitz and Claire Kamp Dush, who found that people experienced gains in emotional wellbeing after moving in with a partner, whether or not they got married first.

The Post’s headline is reminiscent of others on marriage and cohabitation that overstate narrowly bounded empirical findings. Here’s a similar 2012 headline, which I wrote about here: “Marriage is overrated and health and happiness benefits for wedded couples are a MYTH.” While I respect the authors and methods of these studies, and researchers do not control the headlines and emphasis of such media pieces, the message many emerging adults would receive from them is misleading.

What Mernitz and Kamp Dush Found

Mernitz and Kamp Dush examined changes in emotional distress across various relationship transitions, including moving in together, getting married without living together first, and marrying after living together. Using a large U.S. sample, they looked at the first and second transitions of these sorts for people in their twenties. Quoting from their Journal of Family Psychology article, they found:

  • “ [E]ntrance into first cohabiting unions and direct marriages, and all second unions, were significantly associated with reduced emotional distress.”
  • “Gender differences were found for first unions only; for men, only direct marriage was associated with an emotional health benefit, while both direct marriage and cohabitation benefited women’s emotional health.”
  • “[T]ransitioning into marriage from a first, current cohabitation (Table 2, Model 3) was not associated with change in emotional distress; these results held for second unions in that transitioning into marriage with a second, current cohabiting partner was also not associated with a change in emotional distress.”

These results are not surprising to me. There are plenty of reasons that individuals would experience a gain in personal wellbeing, at least in the short term, when they move in with a partner (with or without marriage). You have two people who are in love, who are likely relatively early on in a relationship, who are going to have more time together (and sex, for a while)—it is not surprising that such things might be associated with emotional gains. Mernitz and Kamp Dush’s methods cannot speak to long-term differences between cohabitation and marriage, however, because their comparisons were based on measurement in two-year increments and not trends over longer periods of time. An even greater limitation—which they noted—is that they did not (and likely could not) analyze changes in relationship quality over these transitions. That’s an important variable that one would expect to be associated with long-term emotional wellbeing. Hence, to me, their methods do not support the conclusion that cohabitation has the same benefits as marriage, long-term, for most couples.

Consider two facts.

First, cohabiting relationships are far less stable than marriages. While many marriages end in misery, far more cohabiting relationships break up than end in lasting love or family stability.1 Most couples who cohabit these days do so before having formed or signaled a commitment to the future (marked by marriage, engagement, or a declaration to others that they intend to stay together). I believe that this point is routinely missed by researchers and family policy experts. Part of the power of marriage, for all its historical flaws, lies in the way it can signal an intention of a lifelong commitment between two partners and to those around them in a particular sequence; the formation of commitment prior to living together or pregnancy provides for better relationship outcomes on average. For more on that subject, see this article that I wrote in 2014. I believe it to be the second most important thing I’ve ever written.

Second, the relative instability of cohabitation has important implications for children. An ever-greater number of unmarried, cohabiting couples have children, and these couples are far less likely than married ones to raise their children together.2 And it has become increasingly clear that children tend to fare best when raised by their own two parents. In fact, as Wendy Manning makes clear in a recent review, unmarried biological parents who are continuously raising their children together are likely to see outcomes for their children rivaling those for married couples.3 But as Manning also points out, “Only one out of three children born to cohabiting parents remains in a stable family through age 12, in contrast to nearly three out of four children born to married parents.” This matters because family instability is well understood to be a risk factor for the wellbeing and development of children.4

Some cohabiting couples are highly committed and will build lasting, loving relationships without ever marrying. But, in the main, cohabitation is simply not like marriage when it comes to the level of commitment5 and the likelihood of achieving lasting stability. One can argue that they are alike when controlling for commitment and intention, but that would miss the main difference between the two.

Mernitz and Kamp Dush also found that those entering a second cohabitation (or marriage) after breaking up from a first showed important gains in emotional wellbeing with that second transition. They suggested that this implies serial cohabitation may be less detrimental than others have argued. I have more trouble believing this to be true for most people than believing their basic findings about improved emotional wellbeing from moving in together. Mernitz and Kamp Dush noted that this interpretation is not consistent with other research, but they also suggested that their methods are superior in some ways to those of prior studies on this subject. But I think their findings are really not comparable because they did not analyze long-term outcomes like divorce or marital happiness.6 It’s not that I don’t believe that some people learn something from living with a partner that leads to breaking up, and then subsequently find a better match. It’s more that I believe the complications and risks of cohabitation—such as the inertia of living together, which puts people at risk of getting stuck—prior to marriage or at least engagement outweighs potential benefits for most people.

Based on what I see in the literature, I don’t believe people should expect to cohabit with a number of different partners before settling down, and assume that doing so will improve their odds of lasting love and family stability. That may be the case in the future, but I do not see evidence that that’s how things work now. If you are thinking about this path, consider how you might learn about who is a good partner for you without making it harder to break up in the process.

Emotional Wellbeing or Relationship Quality: An Empirical Quandary

My colleagues Galena Rhoades and Howard Markman and I examined changes in relationship dynamics across the transition into living together in a paper published in 2012 (in the same journal as Mernitz and Kamp Dush’s study).7 Mernitz and Kamp Dush noted they were unable to study dimensions such as relationship quality; our study methods were optimized for doing just that.

Both their study and ours had a substantial strength not typical for this literature. Both used methods that allowed people to be compared to themselves, before and after the transitions being examined. It is more typical in this field to contrast one group (say, married people) with another entirely different group of people (say, cohabiters) while trying to control for important selection differences between the groups. Methods that compare people to themselves across transitions control for some elements of selection characteristics.8 (For more on the subject of selection and how it confounds researchers, see these pieces I’ve written: here and here and here.)

In contrast to Mernitz and Kamp Dush, we were able to look at both levels and directions (slopes) of variables before and after people moved in with their partners. So, for example, we could see not only the average level of commitment to one’s partner before and after moving in together, but also if that variable was rising or falling leading up to the transition and what direction it started going afterward. Mernitz and Kamp Dush had the benefit of a much larger sample; we had the benefit of many more time points close to the transitions, and of more variables related to the quality of the relationships.

Here are a few highlights from our study (all on average, of course):

  • Dedication to one’s partner increases in the lead-up to moving in together but then levels off after the transition. It does not become as high as what you’d expect for those who are going to have a successful marriage.
  • Different types of constraints—factors that make break-ups less likely regardless of partners’ dedication9—show large increases upon moving in together10 and then start to grow more rapidly.
  • Conflict increases and starts to climb steadily after moving in together.
  • The frequency of sex jumps modestly after a couple moves in together and then declines steadily to become lower than it had been before the transition.

Are these findings contradictory to what Mernitz and Kamp Dush found? Not necessarily. There are many ways that serious relationships can benefit individual wellbeing. At the same time, we did find compelling evidence that relationship quality declines after moving in together while the constraints on remaining together increase and start to build more rapidly.

In case you are wondering, my colleague Galena Rhoades and I expect pretty much the same pattern to be true of marriage but with one important difference: partners who wait until marriage or at least engagement to cohabit tend to have higher and more mutual levels of dedication to a future together.11 If your goal is lasting love with a strong relationship as a foundation for a family, think carefully about the conditions under which you’d move in with someone. And decide if you think marriage and cohabitation are essentially the same—for your life.

1. Vespa, J. (2014). Historical trends in the marital intentions of one-time and serial cohabitors. Journal of Marriage and Family, 76, 207-217.  doi: 10.1111/jomf.12083

2. Kennedy, S., & Bumpass, L. (2008). Cohabitation and children’s living arrangements: New estimates from the United States. Demographic Research, 19(47), 1663–1992; Manning, W. D., Smock, P. J., & Majumdar, D. (2004). The relative stability of cohabiting and marital unions for children. Population Research and Policy Review, 23, 135-159.

3. Manning, W. D. (2015). Cohabitation and child wellbeing. The Future of Children, 25(2), 51–66.

4. Manning, W. D. (2015). Cohabitation and child wellbeing. The Future of Children, 25(2), 51–66; McLanahan, S., & Beck, A. N. (2010). Parental relationships in fragile families. The Future of Children, 20(2), 17-37.

5. While the sample we used is older, I do not believe any recent trends would change the finding that married couples have higher average levels of commitment than cohabiting couples: Stanley, S. M., Whitton, S. W., & Markman, H. J. (2004). Maybe I do: Interpersonal commitment and premarital or nonmarital cohabitation. Journal of Family Issues, 25, 496-519. doi: 10.1177/0192513X03257797. And sociologist Steven Nock predicted, in what I believe is the last piece written by him before his untimely passing, that the differences between marriage and cohabitation would become starker over time: Nock, S.L. (2009). The growing importance of marriage in America.  In H. E. Peters and C. M. Kamp Dush (Eds.), Marriage and family: Perspectives and complexities (pp. 302-324). New York: Columbia University Press.

6. Lichter, D., & Qian, Z. (2008). Serial cohabitation and the marital life course. Journal of Marriage & Family, 70(4), 861-878.; Rhoades, G. K., & Stanley, S. M. (2014). “Before ‘I Do’: What do premarital experiences have to do with marital quality among today’s young adults?” Charlottesville, VA: National Marriage Project.

7. Rhoades, G. K., Stanley, S. M., & Markman, H. J. (2012). The impact of the transition to cohabitation on relationship functioning: Cross-sectional and longitudinal findings. Journal of Family Psychology, 26(3), 348-358.  doi: 10.1037/a0028316

8. This is the subject of a paper I like a lot: Johnson, D. (2005). Two-wave panel analysis: Comparing statistical methods for studying the effects of transitions. Journal of Marriage and Family, 67, 1061-1075.

9. Rhoades, G. K., Stanley, S. M., & Markman, H. J. (2010). Should I stay or should I go? Predicting dating relationship stability from four aspects of commitment.. Journal of Family Psychology, 24(5), 543-550.

10. As we predicted in Stanley, S. M., Rhoades, G. K., & Markman, H. J. (2006). Sliding vs. Deciding: Inertia and the premarital cohabitation effect. Family Relations, 55, 499-509.

11. Rhoades, G. K., Stanley, S. M., Markman, H. J. (2006). Pre-engagement cohabitation and gender asymmetry in marital commitment. Journal of Family Psychology, 20, 553-560.