Humans are unusual among mammal species in their strong tendency to engage in long-term sexual relationships. Most mammal dads are deadbeats—contributing their bit of sperm to the reproductive process but having nothing to do with mom or the kids after that.
Among humans, however, monogamy is the norm—a man and a woman (usually, but not always) fall in love and commit to their relationship for the sake of raising a family.
In other words, it seems to be human nature to be monogamous.
And yet, humans quite frequently engage in short-term sexual relationships as well. Even in societies where extramarital affairs are severely punished, the temptation to cheat can be too overpowering to resist.
Moreover, those of us who remain committed to our spouses still feel the urge to try out other sex partners. If it were truly human nature to be monogamous, we wouldn’t be tempted to stray.
It’s important to note that the common belief that men prefer short-term sexual relationships while women prefer long-term ones is not part of this theory, nor is it borne out by the data.
Women who have children need help raising them, and having a man around who’s biologically related to those kiddies—and thus committed to their welfare—is important.
Likewise, most men reckon they’ll get more sex in a stable relationship than if they play the field, so they stick around.
Only a minority of men have what it takes to successfully play the short-term mating game over the long haul, and those who do have little incentive to commit to a single woman.
Players who also feel social pressure to settle down rarely stick to their wedding vows, as attested to by the countless scandals of Hollywood celebrities.
In a similar vein, women who are committed to their careers may decide they don’t want the distraction of marriage and family. But they still have sexual needs, which they meet on the short-term mating market.
Over the course of our lives, most of us employ a mixed strategy of short-term and long-term mating. As young adults, we often pursue exploratory short-term relationships until we find someone to commit to.
And if that long-term relationship goes sour, we once again start exploring other options.
Evolutionary psychology lays out human reproductive practices as a two-pronged strategy, a mixture of short-term and long-term mating- these sexual styles aren’t two separate categories.
Rather, they represent two ends of a continuum ranging from shortest of the all, the one-night stand, to the longest, namely lifelong monogamy.
One example is the friends-with-benefits relationship, which is certainly long term and involves some level of emotional attachment, but without the commitment of monogamy. Another one, is the booty call.