80% of divorces are initiated by the wife.
The stereotype that men, as a group, dump their wives for a younger model isn’t true.
I’d bet most men would stay married if they were allowed to screw around women in general are not going to stand for a cheating husband even if they have cut him off
I think maybe what happens is the man cheats with the younger girl, and the wife finds out and initiates a divorce.
That would explain both sides