I can’t even think of an example of a lead female character who cheated and was taken seriously..except Gabby from Desperate Housewives, which played up various offensive Latina stereotypes.

Otherwise, it’s been virtually all men cheating. When women cheat, it’s portrayed as sad and tragic and motivated by neglect or total personal breakdown. I guess the benefit of living in a society that thinks you’re crazy is you can get away with sexual shenanigans.