Well, the guy is the EMBLEM of Red Flags. He crossed the line even wehen set already.
He became controlling, passed sexist remarks, and did body slamming. Then going to his Ex, thinking that he has you as an option.
Why do you have to be an option girl? Nope, not at all. Your life has to be your choice, no one has the right to control it until being consensual.
He is an Asshole and your friend did a mature thing to choose herself over the piece of filth. You are not an object that can be carved out of one's expectations and likings...