I have several friends who left their wives for some pretty average-looking women. The deal breaker? Easy sex. If you aren’t having sex with a woman, it doesn’t matter what she looks like. I think that is why some men go on the “down low”.
The other are the men who think sex is too much trouble. Lots of them up here in the hills. You find them in the hunting camps. I’m meeting too many men who leave their wives after the kids leave
Chances are good that sex in their marriages ended with the kids being born, so the guys were just being polite hanging in there that long.