10/01/2011 02:31 pm ET Updated Dec 01, 2011

Does Sex Predict Marital Disruption?

Does sex predict marital disruption?

Now I know what you must be thinking. Surely scientists do not need to study this question. We all know the answer without even bothering with some lame scientific study. Or surely this was settled scientifically a long time ago, right?

Well it is always a bit more interesting and complicated. That's what make behavioral and social science fun. We can put our common sense to the test. Kristina Dzara at Southern Illinois University starts by telling us that scientists "know little about the sex that people have while married with their spouse and how it may influence marital disruption," she writes in her article, Assessing the Effect of Marital Sexuality on Marital Disruption.

To examine role of sex in marriage, Dzara used the Marriage Matters Panel Survey of Newly Wed Couples that followed over 1000 couples in Louisiana from 1998 to 2004. The average age of the wives in this study was 28 and the average age for men was 30 years.

The author used three measures of sexuality in the first three to six months of marriage -- frequency of sexual intercourse, sexual satisfaction, and agreement between spouses about their sex life. Dzara used these measures to predict divorce by the 5th year of marriage. As we know, there are a lot of factors can contribute to divorce -- marital quality, early marriage, cohabitation and many more. In order to get a better understanding of the effects of sexuality in marriage, the author controlled for many of these other factors.

So, first, does frequency of sexual intercourse matter in terms of couples staying together? No, say these findings. On average these young couples had intercourse between one and several times a week, but frequency didn't seem to matter.

What about satisfaction with sex and physical intimacy? The author tests this effect for both husbands and wives. For wives, satisfaction with physical intimacy decreased the likelihood of divorce, but overall marital quality and satisfaction with intimacy appeared to have the same effect. In other words, marital quality and satisfaction with sex could not be teased apart for wives.

So what about the effect of husband's sexual satisfaction and the prospects of divorce? The probability of divorce is dramatically reduced when husband's report being sexually satisfied. Dzara writes, "a couple with a husband who has the highest self-rated satisfaction with physical intimacy, compared to a husband with the lowest self-rated satisfaction with physical intimacy, decreases their odds of experiencing a marital disruption by around 83.7%." Overall, husbands' satisfaction with physical intimacy is a stronger influence on divorce than any other measure in this study.

Somewhat surprisingly, agreement between husbands and wives about their sex life did not seem to have much influence on their likelihood of divorce. "Agreement about one's sex life" may be bound up with many other factors of agreement.

In short, sex seems to matter to healthy marriages -- not too big of a surprise. For wives, satisfaction with physical intimacy and marital satisfaction seem to be rolled into one overall factor. Not so for men. When men report being satisfied with their marriage, this reduces their likelihood for divorce, and if they also report being sexually satisfied, then divorce is even more unlikely. The author of this study notes the limitations of this study -- the couples in the study were generally younger and from only one state, so they may not be representative of the United States as a whole. Nevertheless, these seems like important findings to consider.