About ready to give up

I have been married for 12 1/2 yrs, been together for 16 years. We meet when we were both 15 and starting seeing each other at 16. We got married at 20. My parents were against our relationship from the beginning. He is an ex-gang member, left the state, and our ages. They finally approved our dating when we were 18. We snuck around for those 2 years. In the beginning he was outgoing, loved going places with me, helped around the house. We were opposites attrack, got along great, happy always laughing. About 3 years into the marriage he got sick and still is to this day. I stood by him everyday, went to every doctor visit. His illness involves him not being able to eat well and would get sick at any unknown time. We eventually stopped going out to eat,movies, anything where there would be people due to his fear of getting sick infront of others. Our friendships with others dwindled away because he didnt want to go to their house and act like he wasn't sick. He has become a recluse. He wants you to come to our house. Taking care of him over the years has become somewhat of a burden to me. He has gotten so used to me doing everything. He had a fling with my ex-best friend, I stayed. We worked it out and things got better, for a while. He started helping out around the house less and less. I have asked/told that him helping me would be/is very appreciative. I have worked 2 jobs for the past 2 1/2 yrs. He doesnt help. I do all the chores and mow the grass. There is the issure of him enjoying his pain meds too much, wants to find other pain meds. He loves the mind-alterning drugs. When he finds out about these its his only priority. We have grown apart and we have nothing in common anymore. I want to leave,not becuase of him being ill. I could have done that years ago. It's his laziness, unwilling to do anything, anger he takes out on me (mental only). We talked about all this back in April. I left for a couple of days and begged me to come back, he would try anything. He did great for 2 weeks and it went right back. I don't want to hurt him but the relationship is hurting me. He doesn't want me to go out and do things with my friends. I feel he only wants me to be there to do everything for him and so that he's not alone. Oh, there is no intimacy. I'm not in love anymore, and the attraction is gone. He has left himself go. I feel myself starting to resent him at times. There are more issues but I'll start out with this. I would appreciate any comments. Thanks