If you strip away the romance and the complicated societal rules and obligations and general philosophical meandering, humanity’s purpose is very simple: we’re here to ensure the continuation of our genetic lineage. Full stop. Men want to ensure that their own genes are passed along while simultaneously trying to prevent other males from impregnating the same females, thus ensuring that they’re not raising someone else’s child. Women want men whose genes will help ensure that their children will survive to reproduce in turn and who can help raise and protect the child until it reaches maturity. But the ways we have of getting those goals can be tricky. On a strictly reproductive level, men and women both have an interest in having sex with many partners; for men, it helps increase odds of impregnating women with his child while for women, obscured parentage actually encourages a communal responsibility for the child.
And this is without getting into the emotional and social aspects of sex – the use of sex in solidifying communal bonds, the fact that humans are one of three species of mammals that have sex strictly for pleasure, etc.
All of this is a very long-winded way of saying that there’s a scientific basis for the fact that monogamy is hard. So hard, in fact that it’s estimated that somewhere between 30% to 60% of all married individuals in the United States will cheat at least once during their relationships.
Let’s let that number sink in for a minute. Somewhere from between almost a third to over half of all married individuals. And don’t think this is exclusively men; the number of women who step outside of their otherwise monogamous relationships has been rising for the last 20 years.
If you want to prevent your girflriend or wife from straying, then you need to understand why she cheats… and what you can do about it.