In many romantic relationships, one partner desires a higher level of commitment—engagement or marriage—while the other is content to let the relationship stay in its current form. I suspect that, in about two-thirds of these cases, the partner seeking more commitment is the woman while the man drags his feet. And that’s certainly in line with contemporary cultural stereotypes.

The fact that men are legendarily wary of marriage is stranger than it first appears. Both men and women benefit from marriage, but men seem to benefit more overall. In addition to being happier and healthier than bachelors, married men earn more money and live longer. And men can reap such benefits even from mediocre marriages, while for women, the benefits of marriage are more strongly linked to marital quality.

Moreover, according to several surveys dating to around a decade ago, men are more likely than women to say that it’s better to get married than to go through life single, and among the unmarried, men are more likely than women to report that they would prefer to be married. Some recent surveys, however, suggest this difference may have lessened or even flipped, although we still find men a bit more likely than women to endorse the importance of marriage in our lab’s national sample of unmarried individuals.

Logically, then, men should be the ones pursuing marriage: they seem to view it as desirable, and they are more likely than women to gain major benefits from it. So why would men hesitate to tie the knot?

I believe that men resist marriage more than women primarily because they believe marriage requires a substantial increase in their behavioral commitment—and they don’t always feel ready for that transition. Three sources lend support to this theory: (1) qualitative, focus group research by Barbara Dafoe Whitehead and David Popenoe presented in 2002; (2) the findings and conclusions of sociologist Steve Nock; and (3) the work of my colleagues and me on sacrifice and commitment.

Young men associate marriage with increased responsibilities and with a greater possibility of financial loss.

First, let’s look at Whitehead and Popenoe’s research, which was published in the 2002 report of the National Marriage Project. The two drew on discussions they conducted with sixty never-married, heterosexual men, who came from a variety of religious, ethnic, and family backgrounds and ranged in age from 25 to 33. These men reported that the main reason they resist marriage is that they can enjoy many of its benefits without actually getting married—that is, through cohabitation. Further, they reported experiencing almost no social pressures to marry; not from family, not from friends, and not from the families of the women they live with. They associated marriage with a number of increased responsibilities and with a greater possibility of financial loss. I cannot imagine that such beliefs are any less prevalent now.

On a lighter note, men said that one benefit of not marrying was that, if they were to marry, their girlfriend-now-wife would tell them what to do. This could be evidence of an inner view that, after marriage—but not before—their partners have the right to tell them what to do. This is totally consistent with the way stronger commitment transforms one’s sense of a relationship. It’s also amusing to me given the evidence of marriage’s health benefits for men. Most scholars assume that a major reason for these benefits is wives’ direct influence on their husbands’ behavior: “That’s your third beer tonight—why don’t you stop with that?” “You need to go to the doctor and get that mole looked at.” “You’ve been working late every night, running yourself ragged. It’s time to cut back.” It seems younger men may ironically perceive as a drawback an aspect of marriage that is associated with good health and a longer life.

Second, according to the work of sociologist Steve Nock, marriage changes men in fundamental ways. In his book Marriage in Men’s Lives (1998), he discussed how men’s belief systems about themselves and their wives change when they cross the line. His argument rests on the potency of the social role of “husband.” In general, he argued, men begin to see themselves as fathers, providers, and protectors when they transition into marriage.

These changes in identity are associated with behavioral changes. For example, men earn more income when they’re married, work more, spend less time with friends apart from marriage and family, and spend more time with family and in the community in which the family is embedded. (Causality can be argued, but research strategies designed to account for selection effects suggest that on at least some of these measures, marriage does have a causal impact.) In Nock’s thesis, marriage brings large changes in identity for men, and those changes are all in the direction of the expectation of increased responsibility to care for others. The data are more scarce on how women change when they get married; however, there seems to be less reason to believe that women have a similar sense that they or their responsibilities will change dramatically when they get married.

Men begin to see themselves as fathers, providers, and protectors when they transition into marriage.

Third, research on sacrifice in marriage provides another window on potential differences between men and women. My colleagues and I have found that commitment to the future is more important in explaining male attitudes about sacrifice in marriage than female attitudes about sacrifice. There are a number of possible interpretations of findings like this. For example, women may be more socialized to give to others, regardless of the commitment status of a particular relationship.

But I have a hypothesis that goes further: For men to sacrifice for their partners without resenting it, they need to have decided that a particular woman is the one they plan to be with in the future. They need to have decided that “this woman is my future,” and once they’ve decided, the internal transformation occurs. In contrast, I believe that the average woman sacrifices more fully, starting earlier on in romantic relationships, than the average man.

To summarize the main point, getting married has historically brought a large change in how men see themselves and how they behave. If marriage has been a particularly strong signal of a change in men’s committed behavior, it would explain the stereotype of women pushing for marriage and men resisting. Over thousands of years of history, women would have come to expect a substantial change in men from tying the knot.

There may be groups where my theory simply does not hold, or it may no longer hold the way it may have at one time. A number of sociologists have found that the motives to get married or to avoid marriage may be different for those at lower incomes than for those who are middle- or higher-income. Some working-class women, for instance, have revealed in interviews that they resist marriage because it is harder to exit than cohabitating relationships. Further, they reported that men would expect a more traditional division of duties by gender in marriage than is expected in cohabitation. In other words, they reported that the men they knew would, indeed, change after getting married—but that the change would be negative for these women, so they resist marriage.

The motives to get married or to avoid marriage may be different for those at lower incomes.

It is doubtless true that women’s increased economic opportunities, as well as the changes in the roles of men and women in families, may substantially alter the types of commitment dynamics I’ve described. Yet there is a potent counterweight to how far some things can change, and that has to do with the fundamental fact that women get pregnant and men do not. As some scholars argue, given the high personal costs of pregnancy and childbirth to women, it has been crucial throughout human history for women to accurately discern (and if possible, increase) the commitment levels of men. The fact that females have better options and personal resources now than in past eras may well change the equation underlying my thesis, but some behavioral differences between men and women seem very likely to remain because of the biological constraint.

Regardless of how much the behavior of males and females may change in the years ahead, I believe that Steve Nock had it right when, in one of the last works he wrote before his untimely passing, he predicted that marriage would become an increasingly potent signal of commitment as other relationship forms become more common (i.e., cohabitation). Not all relationship transitions are transformative, but marriage is meant to be. That means it matters.

This piece was adapted from a longer scholarly paper by Scott Stanley, available here, which contains additional background and relevant citations.