How Do I get through to her?

Well, first of all I agree with you that there's nothing wrong with leaving a baby in a crib while you get ready for work. At least it's safe there. Also, while I do not condone hitting a female, I would not let one beat up on me like that. When she gets home again, I would simply let her know right to her face that she is not to get physical again with you like that if she expects you to just stand there and take it. If she hits you then tell her she should expect to get smacked right back. After you settle that part of the argument ask her what's wrong with her and suggest some therapy. This is not normal behavior. :-)