Once an abuser, always...?

Hi, I just found this forum.... I was wondering what some of you thought about the idea that if a man, or woman for that matter, is abusive, there is little to no chance that they will ever stop being that way? Is that just pessimism? I believe I am having a hard time admitting that my husband is abusive... because of my parents' experiences, ie my mother's accusations that my father was abusive, it is as if I don't want to admit the same defeat, the same weakness, the same or even greater stupidness for allowing me to get in, and remain in a situation such as this. We are young, really too young, and have only been married 3 years... G has flatly denied me leaving him and said that he would kill me if I left, he would track me down and that would be the end of it. He has a real 'psycho' side and has similarly threatened to kill my grandmother (now deceased)! He has also strangled me and hit me and violently detained me, not to mention playing with my mind to the point of me feeling completely worthless and incompetent and completely, stark crazy. Probably classic text-book, he changes drastically and today, for example, is the sweetest and most thoughtful person... I really do feel like I am going crazy sometimes and think "What in God's name are you doing here with this person, what happened to you?" " and then, immediately, my mind thinks, "why are you making such a big deal, just be happy and get over your depressed state. He shouldn't determine how you feel, shake it off, when you exhibit your weakness, that is when he attacks, the problem starts with you" .... Can he change? What are the chances? When we talk about these things, he is sincerely remorseful, it is as if he can't control himself when his ire overcomes him and he becomes downright frightening... Thank you to all who answer. Peace and wellness to everyone-