Reworded to make sure I'm not being leading. I'll be on the lookout to make sure that standard is applied equally.

Every single woman I know has spoken about a man's change in behavior after they had sex for the first time. That not only did he turn distant, he turned MEAN on her, started badmouthing her behind her back and being hostile to her face.

Nothing happened except they had sex.

Why do some men behave like this?