Because women get pregnant and men do not.
As I man, the last thing I want to spend my life doing is working to raise the kid of some guy who bedded my wife.
And thereby waste my life helping that other guy propagate his genes while he goes merrily on his way.
But my wife would have nothing to worry about, because any child she bears will have her genes no matter who the father is.
In fact, many women are influenced by inborn proclivities, to purposely be unfaithful if they judge their husbands to be only good for supporting the children they have, while at the same time they judge their husbands to lack the best genes for their children.
In other words, their husbands are nice boy suckers. Would natural selection evolve women who would want their own own male children to grow up being nice boy suckers, and thereby fail to pass their genes onto the next generation?
So and usually influenced by inborn proclivities, women marry “nice” boys to help them raise the children of “bad” boys. Aren’t enough bad boys to go around, you see, for every woman to find one to actually marry.
So instead either before or after a woman makes babies with the bad boy, she finds a good boy to marry and help her raise the bad boy’s kids.
And it does no good to talk about how now we have genetic testing and birth control, if our feelings about such scenarios are hard-wired into our genes, which I am sure they are.
“Momma’s baby, Daddy’s maybe” comes to mind.
It’s probably in Proverbs somewhere, I’m not sure.
If it’s not it oughta be.
what???? MANY women do this? MANY women have children with men other than their husbands for this reason?
"shoooo...."