Can I fix anything in this relationship?

We started dating roughly 2 years ago in June, right after I got out of 11th grade for the summer. Everything was perfect at first, we were both super happy as far as I could tell and the first 6 months of our relationship were dynamite. Then I turned 18 and a week later I had moved in with him, his father, and their pets. At first it was ok, but then we started fighting I'm guessing because of his dad and the stress dad put on us because I was living there. I at first slept in the extra bedroom, but eventually wriggled my way into just sleeping next to him and his dog every night. He may have been a little upset that I did that, because he was used to sleeping alone and being able to stretch out. I just wanted to be as close to him as possible, because he means the world to me. Time progressed and the fighting would come and go, I tried not to be objectionable or hard headed because it only made things worse really. No matter how hard I tried we still fought, over stupid things...it's like our life was perfect but we couldn't live together without squabbling over petty things. In the meantime of all the fighting, I had my senior year of high school which I was tanking and while I was at school he would go to a friends house. I never saw anything wrong with it at first, until he started spending all his time sleeping while I was home and spent all his waking hours either eating or spending time with her. My brother and our friends started telling me he was laying his head in her lap on our friends couch and how they would spend all day at her place. I couldn't help but start to worry that she was trying to replace me. Jealousy just radiated from me, I could never prove he was doing anything wrong, and he had never given me a reason to ever think he was cheating. He wasn't that kind of guy, he said so neumerous times and I believe him. As far as I know he's never lied to me, he's never cheated...anything. So I failed Gym class in highschool and I was on my last week of summer school Gym so that I could graduate, and things in our relationship were rocky as ever. Then the day before the last day of summer school, we were sitting in his room and we were really quiet and then we said it. I can't remember it word for word because my heart has blocked it out...something along the lines of he "can't do it anymore" and I asked if "we could stay together" and he said "i don't know" and I said something like "well if you want me to go tell me" and he said "I think you should go home" or something...the whole time both of us were in tears and we could barely speak. Iwent home to my parents house with most of my stuf that night because I couldn't stay there with him without crying. When I went to leave he gave me a plush fox (his nickname was fox) and he hugged me so hard I thought my chest was going to collapse. Both of us in tears I kissed him one last time and left. The next morning I had to sit outside his house and wait for my Aunt to pick me up and take me to the last day of summer school. I cried all day at summer school of course. The relationship had "ended" but the after math had just begun. We may have broken up, but instead of hating eachother like most couples, we became friends with benefits. I would go back to his house to spend time with him and collect some of my stuff I forgot to pack and we wouldn't be able to keep our hands to oursleves. Over time we have stopped sleeping together completely, and it feels more like I have to beg him to spend time with me. He still means everything to me, and I can't get him out of my mind or my heart. He said he was done with dating for awhile, that he wasn't going to replace me with someone else. I tried to move on thrice, and I kept wanting him instead. The first guy I tried to get with my ex hated. Then my ex told me he still loved me and so the new guy I was seeing ended up not working out, I basically sabotaused it myself because I couldn't stop talking about my ex...same with the other relationships...I ruined them because I had already chosen my ex and I didn't want anyone else. I haven't seen my ex in a few weeks at least, my visits have become less and less because he's says he's busy. But every time I do go over, we sit around and barely talk, he plays games and I cuddle with the dog on the couch and watch him play. That or I play video games on his bed and he sits in his recliner with his DS. My question is this: Is there anyway to fix this? Can I change something or do something to make him happy again? He means the world to me, he always has. I love making him happy, to hell with the expense or effort I have to give to make him happy with me again. I would go to the ends of the earth just to have him tell me he loves me again.