He could of just walked off, but instead took all the hits, grabbed her (which he should of did in the first place), she stopped hitting and pushes him back, he starts throwing full force punches after she had already stopped.
I think he took the punches just so he could hit her back like that, hes obviously got some pent up anger for her. She was barely hitting his big azz, he had no reason to go full gorilla arms on her.
I wonder if he would swing on a man like that.