GENDER DIFFERENCES IN RELATIONSHIPS

I sometimes listen to a radio show on NPR entitled Philosophy Talk, and one time John Perry, one of the show's hosts, said something that really struck me: he pointed out that if male humans had not evolved to be the way that they are, the human race would have died out thousands of years ago.  But the more civilized that the world has become, the more their masculine ways have become a disadvantage.   For example, being physically aggressive was a good thing thousands of years ago when humans were competing for their survival with other species, in fact it was necessary for hunting food and fighting off predators.  But now we live in a world where over ninety five percent of all violent crimes are committed by men, and almost all violent behavior is frowned upon unless it's in response to other violent behavior.  It would appear that evolution needs to catch up to civilization.

Our primitive past also plays a role in our sexual and romantic relationships.  Again, thousands of years ago when we were fighting with other species for our very survival, certain tendencies arose; the bottom line for any species survival is to produce as many healthy offspring as possible.  Now consider that if a man has sex with a hundred different women in a year,  it's possible that he could impregnate all of them, whereas if a woman has sex with a hundred different men, she can only get pregnant once. So you can see why promiscuity in men was necessary to human survival, with healthy, strong men passing on those good genes as much as possible.  Today this manifests itself in the unfortunate stereotype of promiscuous men being haled as studs and promiscuous women being branded as sluts.  It also explains why men tend to avoid committed relationships more than women, and are more likely to stray when in one.  Evolution has just led men on average into wanting to have sex more often, and with more partners, than women.

The sexiest man alive in 1989 was almost 70

Evolution has led to another unfortunate stereotype: that men age better than women.  Almost from the very beginning, movies have matched older men with younger women romantically, with little protest from audiences (Fred Astaire used to say that as he got older, his leading ladies got younger).  Again, this is due to evolution and human reproduction: putting it simply, the main reason men and women are attracted to each other in the first place is the animal instinct to produce offspring.  Even if you don't want to have children, your unconscious mind is pushing you that way, and women, unlike men, lose their natural fertility as they get older.  Generally speaking, a woman past the age of forty is not likely to get pregnant without fertility treatments.  And while men at that age do see a reduction in their overall sex drive, their ability to reproduce remains, and there are men in their sixties still fathering children.  So the sad spectacle of the older man divorcing his wife for a younger trophy wife is based on human evolution.
And it has added an interesting wrinkle to women's desire also.  In their highly entertaining book SEX AT DAWN, authors Christopher Ryan and Cacilda Jetha point out that in the distant past, promiscuity may have had an advantage for women too.  It's safe to say that, centuries ago, the infant mortality rate was very high, perhaps as much as %50.  Humans, unlike so many other animal species, spend the first few years of childhood being completely helpless and reliant on adults (compare a human baby to a newborn zebra that's up and on its feet within minutes of birth).  And a woman nursing a child needed help from others, usually men, to bring her food.  Now, if there are more than one man in the tribe who think that they may be the father of a child, then there'll be more than one man feeling obliged to help feed and protect that child, and its chance of survival will increase. So in the days before paternity tests, women's promiscuity may have also played a role in our survival as a species.

You should really read this

So should we just throw up our hands in defeat and say that all marriages are doomed?  That evolution has led us  too far away from monogamy for it to ever succeed?  Of course not, (although open relationships in marriages can work in some cases).  The nice thing about humans is that our brains are big enough that we can resist instinctual urges.  Consider, for example, that humans, like our distant relatives the chimpanzee,  have been omnivorous from the beginning.  And yet there are millions of people that are vegetarians and vegans, and they're perfectly happy to avoid the animal instinct of eating meat.  So long term monogamous relationships are possible, because, as we all know, humans are both animals driven by instinct, and something more.