Sarah and Sean just got married. They met each other through a dating website three years ago, and after six months in which they spent more and more time together, Sean often staying overnight, he moved in with Sarah.

It seemed the logical thing to do; they felt comfortable with each other and it would save travelling time and money. It would also, thought Sarah, be a test of their relationship and whether it could lead to marriage. But it was another year or so before she raised the subject of marriage with Sean.

He said they needed more time. A wedding would be expensive. But Sarah, 30, wanted to have a child, and she wanted commitment. Sean, 32, didn’t want to lose her, so he agreed. They got engaged and a year later they tied the knot in the company of family and friends.

Have they done a good thing? Objectively, yes. Marriage means commitment and greater stability.

Did they get there in the best way? No, as a new report on this much-debated issue confirms.

Will the marriage last? Maybe.

In What’s The Plan? Cohabitation, Engagement, and Divorce, family scholars Scott Stanley and Galena Rhoades present new data from the United States showing that Sarah and Sean significantly increased their odds of divorce by several false steps.

They had no plan before their lives became entangled. They got together for the worst reasons, and they stayed together partly through inertia – that is, because it would be harder to break up.

Yet this fictional couple’s path to marriage is, on the surface, a typical one today. Under the surface there are differences, but upwards of 70 percent of people marrying now have already cohabited with their spouse, and often another (or other) partner(s).

The majority of people think that’s fine. Many even think that, given high divorce rates, it is good to test-drive your life partner by living with them first, that it makes for a stronger marriage.

But, sorry, that’s misinformation.

What the evidence shows

Stanley and Rhoades, who have studied the subject for many years, say that there is “no evidence” that cohabitation leads to more stable and happy marriages, and “a lot of evidence” that it does the opposite.

“That is, for decades in the U.S. living together before marriage has been associated with greater odds of divorce and/or lower relationship quality in marriage, and not just in a few isolated studies,” they point out in their report.

In their own new study of 1,621 U.S. couples who married for the first time in the decade 2010 through 2019, 34 percent of marriages ended by August 2022 among those who cohabited before being engaged or married.

Among those who lived together only after being either married or engaged to be married, 23 percent divorced or separated. (There was a difference between the latter sub-groups but it was not statistically significant.)

Relatively speaking, those who moved in together before getting engaged or married were 48 percent more likely to see their marriage end.

The selection debate

For those who think there is no difference between cohabitation and marriage other than a big expensive wedding, that is a discomfiting figure.

They may shore up their position by pointing to evidence of selection. This refers to the differences that exist between people before they cohabit: socio-economic status, for example, or having already cohabited, perhaps several times, which carries a greater risk of marital breakdown.

Scholars who hew to this explanation have also argued that, as cohabitation became widespread and accepted, the selection effect would disappear along with the apparent risks of premarital cohabitation itself.

Selection is certainly an important part of the story, say Stanley and Rhoades, but the data continues to suggest that the experience of cohabitation itself plays a decisive role.

Cohabitation and inertia

For one thing, it changes how people think about marriage and divorce: research has shown that having more experience over time with cohabitation decreases positive attitudes towards marriage and increases comfort with divorce.

More important, though, is the inertia that cohabitation produces. One or both partners may sense that the relationship is not going anywhere but it’s easier to stay together than move out. Shared friends and property (who keeps the lounge suite?) would be among the constraints that keep them together.

Having become – to quote one scholar – “prematurely entangled” they get stuck and lose other opportunities to choose a spouse. When they do marry they may come to regret that.

What difference does engagement make?

Quite a lot. It shows the couple have thought about what they are doing and have a plan. But timing is critical, say the scholars.

If Sarah and Sean had talked about marriage before he moved in with her, and they agreed that marrying was the plan, their marriage would be more secure. The clearest sign of that agreement would be their prior engagement.

In their latest study Stanley and Rhoads found there was not much difference in divorce rates between those who cohabited only after marriage and those who did so only after becoming engaged.

What about those who were planning marriage but were not engaged?

Those who were engaged before cohabiting were 11 percentage points less likely to end their marriages than those who reported having marriage plans but not being engaged (4 percent).

“We have plans to marry” is just not as clear as “We are engaged.” “Plans” may find partners on different pages about commitment.

Are these differences, again, down to selection? Not noticeably, report the researchers. Those who were engaged before living together had similar risk factors to those who did the opposite – for example, already having a child with their partner or with someone else – but were less likely to divorce.

Sliding versus deciding

Not all unengaged cohabiters are the same, of course. Some are more deliberate about taking this step than others, though they are a minority.

Stanley and Rhoades asked their respondents whether they “slid” into living together, talked about it, or talked about it, planned it and decided together to do it. Two out of three (64 percent) said they just slid into it, a finding that aligns with other surveys.

This increased the sliders’ odds of divorce or separation compared with the deciders (34 percent vs 21 percent) although this gap reduced to (a statistically insignificant) 6 percent when demographic differences and personal relationship history was taken into account.

However, say the scholars, that 6-point advantage may still matter; an earlier study of theirs found greater marital happiness was likely among those who had talked about the move and decided on it together.

Reasons for moving in together

On the other hand, decisions can be based on faulty reasoning. Motives like convenience and financial benefits – things external to the relationship – that influenced Sarah and Sean’s decision to cohabit are among the worst, prematurely increasing inertia, while the motive of testing the relationship may be “uniquely bad” say the scholars.

“In fact, we believe that people who are moving in together to test a relationship, as the primary reason, likely already have some concerns about the partner or the relationship. What they are doing by moving in together is making it harder to break up with someone they already have doubts about being with in the future.”

The risks of serial cohabitation

If premarital cohabitation with one partner increases the risk of divorce or separation, what is the effect of having lived with one or more prior partners?

The growing phenomenon of “serial cohabitation” complicates the picture of marriage and marital success considerably, Stanley and Rhoades note. Importantly, it makes marriage less likely altogether.

In their sample of people who did marry, there was little difference in the odds of divorce between those who cohabited only with their spouse and those who had lived with one prior partner (26 percent and 24 percent respectively of these marriages ended).

Among those with two or more prior cohabiting partners, however, the dissolution rate shot up to 46 percent.

Clearly, selection plays a large role in these findings, say the scholars. Considerable research shows that having a greater number of cohabiting partners is associated with factors such as economic disadvantage and difficult family backgrounds. Still, experiences within those cohabiting relationships may make the odds of a stable, happy marriage – or any marriage at all – even worse.

Apart from such disadvantages, having lived with a series of partners “may increase one’s awareness of there being other potential, perhaps better, partners out there, which can make staying committed more of a struggle,” and make people more open to divorce. The likelihood of having a baby along the way also increases, and bringing a child into a marriage can be a challenge to the relationship.

Takeaways: Resist hype, reduce your risk

Stanley and Rhoades are seasoned researchers and their data accords with many other studies. When they say, “Don’t believe the hype that living together before marriage will improve your odds,” they should be taken seriously.

They end their report with seven pieces of practical advice that the Sarahs and Seans of the world – and those who want to help them – should carefully consider.

Perhaps the most important is this: having any of the risks for difficult relationships does not mean that a person can’t change those risks. Identifying them, going slower, and deciding on relationship steps can change them. Especially, it seems, if couples get help.

“One rigorous study we conducted showed that a commonly-used relationship education program (in a workshop format for couples) completely eliminated risks to marital quality and divorce for couples who had cohabited before marriage or before having clear plans to marry,” say the scholars.

“The risks of cohabiting before there are clear plans to marry are real, but there are ways to lower the risk for those who have walked a riskier path.”

What’s the Plan? Cohabitation, Engagement, and Divorce. By Scott Stanley, PhD, Research Professor in the Psychology Department at the University of Denver, and Galena Rhoades, Research Professor in the Psychology Department at the University of Denver. Published by the Institute for Family Studies, April 2023

Carolyn Moynihan

Carolyn Moynihan is the former deputy editor of MercatorNet