Oohh, that's harsh.
I don't suppose there's any chance she might be willing to recognize that she has a problem? I mean it could be hormonal or otherwise chemical. Sometimes just getting the right prescription med can help. And it would pay off for her personally too, because she'd feel better. It can't feel good to be mad all the time, it just can't.
Anything in her past? Could she have PTSD? Just wondering.
Love means never having to say, "Put down that meat cleaver!"