Why is sex so frowned upon for women?

Genuinely just confused. A few months ago my guy friend and I hooked up, I was on a break with an ex, he told me he and his girlfriend broke up and he moved out. I found out he lied about that, and she's pregnant. She heard from a little snitch that we had sex and she's mad at me, not him. Because he's the male, "he can't control his urges"...?! Does this make any sense to anyone?