Very confused

So I've been with my bf for almost a year we have known each other for 4 years. I felt like the happiest when we first started our relationship, he was my best friend. But as months passed I feel like he was getting "attached" I don't know how to explain it but it got to the point where he was always questioning me , trying to check my phone , always starting arguments for no reason (why did I tweet that? Why didn't I answer? Wtf am I doing?) so on & on. None of my friends like him because he has hurt me in the past & he is still hurting me now with the way he's acting. I've realized that he is a very self conscious person, he feels like "I'm too good for him" before I didn't feel that way because I thought he was all I needed, but sadly now I'll be moody around him & call him mean names. I've stayed with him in hopes of him growing up. He has never accepted me in any way, it's his way only. I feel so trapped sometimes, sometimes I feel so sad. I know that if you're unhappy you should leave the situation NOW. But it seems like I keep giving him chances hoping he'll mature & actually love me like he says he does. He is a great guy he will do anything for me & I know he wants to change but He is still the same, I have begged for him to change his ways. I have left him before so he could think about his actions after 2 months we got back together & the same **** started going on... He's those emotional type of guys, he cries a bunch. Another thing is , he's always playing the "blame game" & he is so stuck in the past. He's still acting the same. He still doesn't let me be me. He's still controllive. I'm in this position of confusion it isn't hard for me to leave him but I just want to keep helping him out still hoping.. But it's been 6 months now of me feeling this way & im still trying to keep this together when I know this isn't what I want. Hes such a good guy honestly he just doesn't know how to control himself , he doesn't trust or respect me when I have done nothing for him to feel this way. I'm just confused if I should keep trying or let go? It's just so hard to leave because he is loving , he just likes arguing about petty ****. He literally argues about dumb **** every single day, I'm just tired of it. He never listens to how I feel because as soon as I say something he turns the table. I know I'm not as mature but i know what I want for my future, I used to see him in my future & we talked about marriage & moving out. Now when he brings up that topic I cringe because I'm pretty sure I don't want to live with someone that's gonna argue with me every day . I guess I'm just still hoping for change, I tell myself to leave him, my friends say the same I just don't understand why I keep wanting to help him.