Sorry, your EX is f**ked in the head.
A friend of mine a 5'10" 250 power lifter had a girlfriend 5' 90lbs tops that used to scratch or hit him with her fists or throw heavy objects at him because she liked to fight, it was exciting to her but he'd sit there and take it. When he didn't reacted she accused him of not loving her, that he'd found someone else, yahda yahda. They would get together and breakup every few weeks for 8 years, they got engaged and shortly thereafter she got him in the face three good and bloody scratches across his face and he had finally had enough.
She was a real head case too, everyone was overjoyed when he finally dumped her ass.
A lot of guys I grew up with or have known in passing love those wacko bitches, high maintenance, either coke heads or always drink too much and have so kind of "drama episode" every time they go out in public, either fighting with other girls or with their boyfriend and interesting enough they were always those short little 90lb girls.