Long but please read I'm so hurt and I need help

we've been dating for 14 months. We are fairly young and were each other's first real love and first real serious relationship. I found out 4 months ago that he had been sexting other girls. Then it came out that he has had a very bad porn addiction for many years. He would watch rape porn and save random nudes on a secret gallery on his phone and use it nearly everyday. He always fantasized about other women and checked people out in public all the time. He use to tell me who he would fuck if he had the chance and tell me all about how hot other girls are. He always said that sex wasn't that important to him, but he would constantly be thinking about it. Every time we hung out he just wanted to have sex. He was constantly thinking about other women. Constantly using porn. He never directly pressured me into anything but he basically would tell me that he would leave a girl that didn't have sex with him often enough. So I would do it even when I didn't want to so he would like me. I never wanted to be rough but he always was. He always begged me to send him nudes. I eventually did and I hated myself for it after. When I found out the severity of his issue and confronted him he called me insecure and crazy and told me that no other girl would care and a whole lot of other mean shit. After a long time of fighting and me making him understand how I feel, he is changing. He stopped all forms of porn. I have full access to his phone and all accounts. He only gets off to pictures of me now. He has promised that he understands and he is so sorry for what he did and he hates who he was and he wants to be a better man for me. He says now he only wants me and he will never ever hurt me again. He claims to have stopped staring at other women in public but who knows if thats true. Basically he was awful to me before But he has promised to and so far done a pretty good job at treating me right from now on. The past still kills me. It's so painful to know that he cheated on me and that I was never enough for him. I feel like I was just a body to use. We had plenty of good times too of course. I love him with every single part of me. But I feel like he never loved me until he realized that he was going to lose me. Can somebody please give me some advice. I have no idea what to do.