I don't think it's okay what either of them do to one another. Whether it was or wasn't self defense, the pair of them are at fault in my opinion for continuing the relationship.

But... if she knows his temperament, and knows what she can reasonably expect from him into the future, it becomes harder and harder for me to believe that she's just an innocent victim in all this.

It's not right what he did, but she's going straight back for more, so she deserves to share the blame with him for anything that happens into the future.

She's a woman of means who can afford to get otu of this relationship, but she chooses not to.