Aries-Pisces Dilema

Hello everyone, newbie alert haha* I've been reading for quite awhile and decided to join. I enjoy this forum tons!
Anyway here is my delimna. My Aries and I have been dating on and off for about 5 months. When we met we both wasn't ready for a relationship I never told him but he told me flat out. Now I would be lying if I said I didn't want him to commit to me but sometimes I like things just the way it is but most of the time I don't. And I don't think he wants to or is ever going to commit to me. He is so selfish and he says the most hurful things to me, the things he says to me makes me wonder how on earth can someone be so cruel. Now the issue of the ex, she leaves in another state his hometown. They dated I don't know for how long but she dumped him for her an ex-boyfriend, she has a baby now and is getting a divorced from another guy. He moved down here because he couldn't deal. It's been 2 yrs and he's still in love with her and that's fine but what hurts is he constantly throws it in my face that she's the one and he'd give up everything to get back with her. My issue here is not the fact that he loves her but why must he always bring her up to me all the time, the women he dated before me he never once mentioned her! It used to hurt before but I eventually became numb to it and I told him so. There are so many times that I walked away but somehow I always ended up going back to him. I asked him, no begged him to let me go because he's hurting me and I know it's strange but it's easier for me when I'm the dumpee instead of the dumper but he refuses and tell me it's not what he wants blah blah blah. About two weeks ago I found the strengh I needed to tell him to leave me alone(I felt so horrible)he almost went crazy, he never blew up my phone but other things he did I knew he was miserable, won't go into details I just knew. He's the lead singer for a local rock band and really really handsome and alot of girls like him. I'm like why can't you just leave me alone, you have so many options, why do you refuse to let me go? His friends doesn't like me and the few people who know we're dating think we're such an odd couple I'm black. I don't know, how can I find the strenght to walk away and stay away. Please help... I'm moving to Carlifornia in March but I can't wait till then.