He stares at women in public and rubs himself on me

I have been with the same man on and off for 5 years.. We started to get married a few times but I just couldn't do it because he has problems with lust and he loves it more than me. I know he looks at porn, { pics and movies } because I have found books, vhs tapes and the crap on the computers. We have fought about it numerous times.. His problem with lust is so bad that he can't even watch a regular movie with the people fully dressed without going into fantasy land. His touching himself so much during movies has taken the enjoyment out of watching movies or even regular tv from me and then he has the nerve to get upset at me for not wanting to watch movies with him. I hate to go out in public with him for fear of how he will hurt me next. I've seen him staring at women when we are together and he used to pull me close to him and rub himself on me when he would get excited at looking at them until I realized what was happening and stopped it. When we do go out together, most of the times I keep my eyes on the ground now so I wont have to see who he wished I was. I can only wonder how many times he had sex with me while he was on me..... Just a little over 2 weeks ago was the last time I found porn on his laptop { also the last time I looked }. I told him that we were over and he for the first time confessed to me that he was a sex addict. He has not went into detail about it but I truly believe that besides the porn, fantasy, and masturbation, I also believe in my heart that he has had sex with other people sence we have been together. I don't know if he admitted having problems because he loves me enough to want to make us work or if he only told me that because he has no where to go. He has no family or friends to turn to and no money to get his own place. He is in his 30's but he is not a responsible person and can't make it on his own. He thinks money is only for the enjoyable things in life. He lived on his own for a short time and was not good at keeping the bills paid or makin sure he had enough food. He got a roommate and he still couldn't keep up with the bills. I loved him and wanted to marry him and had hope that he would change so I asked him to move in with me. He did not change and we did not get married. I believe he does love me some, but just how much I honestly don't know. I don't think he's capable of loving anyone very much anyway. But I am getting ok with that now because I don't love him as I once did. Too much pain cuts love way down. Although I do still love him just not as I used to. He was married before and has a child and lost them because of his problems. He hasn't seen his child in years or hasn't even talked on the phone. It is a great fear of mine that if he doesn't help himself that he will end up molesting his child when they do reunite. I know that he lusts after early teens. I fear he lusts after children even younger, although I have no proof of that... He says he is trying to change. He has done some research and some posting. He has admited to me that he is a sex addict.. Those things are more than he's ever done but I am still afraid to believe in him because of so many lies..