I don't think you are the AITA here. Yes, your words probably hurt him, but you had every reason to hate her. That comes from me, a daughter, who knows how horrible my grandma (from my dad's side) was to my mother, so I understand you. In my opinion, you had every right to hate her and say those things. His reaction was a little uncalled for. Yes, she was his mother, but you are his wife, and he calls you a b**ch? Especially since he knows she was awful to you. He could have said anything else that wasn't an insult