If you want to break up with him then do it. You can't have a relationship without trust....it'll make your life a misery. In my eyes I can't understand how he can say he loves you and do that....he seems to be overstepping the mark as far as "flirtation" goes and I wouldn't put up with it at all. I am married to a Leo...and yes he can be flirty, but not in a threatening way like that.Your boyfriend obviously knows that his behaviour is upsetting you so the ball is really in your court.