I had a very controlling BF when I was in my teens. He had also become very abusive. The first "incident" he demanded that I quit smoking, he didn't ask and he made it clear that it wasn't because of health worries. He smoked as well. I told him I'd consider quitting if he did too. He blew up and ended up throwing me in a freaking creek and broke my finger. That was the end of our relationship, but a few years later he had exposed a VERY traumatic thing that I'd gone through and he beat the hell out of me! We were actually in high school when it happened and not dating, but he took me by the hair and repeatedly pushed my face into the floor. Thos school buildings have very hard flooring and it damaged my brow bone permanantly and I had knee problems for a couple of years over it. He fought me for a good 20 minutes before a teacher stopped him. I never went back to school after that.
So, to me, a controlling person should always be stopped or broken up with. There's a difference in controlling and insecure. I can understand some men feeling uncomfortable in certain situations and wanting their partners to be faithful. I can understand that in any person, but there's a real fine line between a little worrying/insecurities and a controlling person who is capable of beating or killing you. I think it should be dealt with very firmly! I don't think a break up is all a person who beats a woman needs.