Boyfriend, ADHD, and lots of anger

Hello, I have been dating a wonderful man for 4 months now. In those four months our relationship has completely spiraled out of control. Some of it I feel is me not understanding his ADHD. Him not communicating, and possibly the fact that he feels like he is an alcoholic.  THere is no talking to him. He shuts down immediately when I try to quietly communicate my views. As I read more into ADHD I am seeing things that trigger his shut downs, but I did not know it would be something I need to research before starting a relationship. I do want to be with him and work things out but I feel that his mood swings and his anger towards me belittles me.  Some of his comments are extremely rude and I am not sure if it is him or just the ADHD.  He constantly tells me we were a mistake and that he doesn't want to be with me. He has left me because he couldn't "stand to be around me" anymore because I was having a down day. I don't feel like the only person in his life, he constantly talks about his ex when he drinks and makes me feel like I don't amount up to her even though I do everything I can to make him happy. I try to talk myself down when he starts his mood swings and try to leave him alone (as he has asked me to do) but then he gets mad because I am not paying him any attention.  At this moment our relationship is so strained I don't even know where to go. I would like to get as much information as I can to continue to try and help him work through this because I am not ready to give up. I just don't know where to go from here. Any help or direction would be greatly appreciated.


~Lost and confused.