A number of species of animals are supposed to be monogamous, sometimes over the course of a lifetime. When the offspring of these various species are analyzed by examining their DNA, it turns out a small , but significant, number are fathered by someone other than the presumptive father. In other words, even in seemingly committed couples, there are infidelities. There is a theory about primates that suggests that monogamous pairs tend to predominate in species where the male and female are approximately the same size. When the male is bigger than the female, as is the case with apes, the male tends to have a harem. By that standard, one might expect that male human beings would tend to have multiple wives or other sexual partners. In certain cultures, this is certainly the case. Muslim men and, in previous times, Mormons, have no restriction, or only a small restriction, on the number of wives they can have. In the bible, the ancient Hebrews had more than one wife. Nowadays, of course, it is considered immoral and improper for someone married to have more than one sexual partner. This is a rule that is violated frequently, sometimes creating a public scandal; but there are clearly men who remain faithful to their wives over the course of a long marriage.
Just how many men are faithful to their wives is difficult to determine. There have been studies based on the self-reporting of men; but these may not be accurate. Men have an understandable inclination to lie about doing something everyone agrees is wrong. Still, studies by Kinsey and Masters and Johnson suggest that about 50% of men are faithful to their wives. Theses studies were done some time ago and followed a period of time when men were separated from their wives for long periods of time because of war. Surely, the meaning of an infidelity when someone is necessarily away from a spouse is different than when they are living together. Also, the number of infidelities in couples who have been married for only ten years, must, surely, differ from those couples who have been married for twenty five years.
Over the years, I have spoken to a great many men who had affairs, some rarely, almost inadvertently, and also others who were constant philanderers. Perhaps I will write a blog on what seems to motivate them. One problem, however, is that they rarely know themselves what motivates them. I have noticed, on the other hand, that the men who are faithful seem to fall into different, somewhat overlapping, groups:
1. Some men simply have very little interest in sex, within or outside the marriage. I think that these are the men who have set down the various rules against different kinds of sexual behavior.
2. Some men are shy. They may be in a position where an opportunity appears for an illicit sexual encounter; and they, sort of, don’t react until afterwards. Sometimes they report these minor encounters to me with a vague sense of regret (not really much regret, however.)
3. Most men who are faithful are simply too busy in their lives to have much time for an affair. They are preoccupied with work, with dealing with kids and a home, with various social activities. Having an affair seems too time-consuming and not worth the effort. Most of these men aren’t thinking of affairs in the first place.
4. Some men say they feel uncomfortable lying and practicing the various complicated deceits required to successfully pull off having an affair.
5. Some men say that the stakes are too high. They know that their wives would feel terrible if they were discovered to be unfaithful; and, possibly, their marriages would be at risk.
Two observations: Whether men, or women, for that matter, have affairs seem in my experience to have no relationship to whether or not their sexual relationship with their spouse is good or bad. Some unfaithful men report, for instance, that sex with their wives is fine. Some men have had no sex with their wives for years. Some of them are very unhappy with this state of affairs, but as a group they seem rarely to go to the trouble of having sex outside of marriage.
When the subject of having an extra-marital affair comes up, men who do not have affairs give some version of the reasons given above for not doing so. Surprisingly, considering what one hears in religious or political settings, very few men say that they are faithful because that is the only morally correct way to live, or they are faithful because that is what their religion tells them.