I'm sorry you had to go through a domestic violence situation. Yeah it would have been nice if she would have never punched and hit him in the face or if he would have walked away and never hit her but unfortunately the situation got the best of them and they reacted in the moment.
I just don't feel that they can go by the resulting damage to determine who is at fault. I have watched a lot of MMA fights and just slightly different placement of a punch can "rock" or "stun" a fighter or cause a knock out. A person could seemingly land 10 solid punches on another fighter and then get hit in the right spot and be out cold.
I wish these two could just kiss and make up though.