Boyfriend soon to be ex- reassurance its over would be nice?

I've been dating him for 6 years on and off. we love each other but lately I've come to terms with the fact that its just not working out. I'd appreciate feedback as far as my decision goes AND how to leave a six year relationship is cold turkey the best way or slowly breaking off contact. I grew up with this guy so its difficult. he seems to have a minor drinking problem and has become violent once with me. he apologized and felt shameful of his actions but the next night he sat on the phone and told me I needed to be "reborn" he also says things like " you think your better than me?" when hes angry. He also told informed me when he was drunk that he believed that I was younger then him mentality wise. He says things like "your just a girl" in the negative way. He has also said Im just a bag of emotions and things of this nature. He has criticized me many times and I wonder why. Is it me did I become a walking doormat or is it him? Is he just an overcritical asshole? I feel like I demand respect just fine and I have left but the stories the same in the end he tries to be controlling and he tries to dictate my behavior. What I find funny, what I find interesting etc.