I love him, but something is wrong. What do I do?

Okay so this is a very long complicated story, but I will try my best to keep it as short as possible while still giving you enough information to help me out. So there's this boy that I have liked since freshman year of hs.[im a junior now] We've been through a lot together and some of the best days of my life we're spent with him. We really got to be good friends in sophmore year though. We spoke all the time, and we spent a lot of time in school together. He would put his arm around me, or come up from behind me and hug me, and he basically was very comfortable touching me. He even grabbed my *** a few times when I was at my locker. lol. Now to make everything clear, we never were in a relationship nor did we ever share a kiss. He has known that I like him for a very long time. That was never a secret. So sophmore year ended really well with him. Even though he had a gf most of the time, he still did things that we're kinda flirtacious. This year started off okay with him, but slowly got pretty bad. At first I thought it was because we didnt have any cles together anymore, but then he stopped speaking to me completley. He won't even look at me anymore. At the beginning of junior year although we didnt talk as much, he still made an effort to be around me once in a while. He came up to me one day at lunch and started to rub my shoulders kinda seductively and he kept doing stuff like that. Things kinda changed after my Sweet 16. I had invited him, knowing that he prolly wouldnt come since that isnt his thing, but hoping he would because I told him how much it would mean to me.He finally decided to tell me that he couldnt come to the party because he was going to florida the next morning.[i dont know if he was lying or not.] When he told me, it was online, and I gave him a little bit of an attitude so he asked me if I was mad at him and i had asked him if he even cared if i was mad, and he said he did and to tell him what was wrong. At that moment, I told how important it was to me for him to be there and how I still had feelings for him. He told me that he was sorry if he ever hurt me and urged me to tell him more because he said it would make me feel better. The convo didnt end badly, it was just kinda w/e. He spoke to me after that convo once or twice, but the talks were quick and neither or us mentioned anything. Then we went MONTHS without talking or even looking at eachother. Then one day he sat down at my lunch table and was sitting directly in front of me talking to one of my friends. We didnt speak for half the lunch period. Finally he looked at me and smiled and asked me why i was mad at him and why i never talk to him anymore. He even put his arm around me like he used to during lunch. We didnt talk much for that convo either, but the day later we went back to not talking. On the Junior cls trip we went upstate and spent the weekend in a hotel. When he saw me in a bikini there, he smiled and was like "yeah." Then when i got cold on the trip I asked him for a sweatshirt after not talking to for months as a test to see if he cared, and he gave me one. And when I have it back to him he went to hug me when i was about to walk away. That confused me since if anyone was to give anyone a hug I thought it should have been me to thank him for the sweatshirt. I didnt know why he would hug me but I accepted the hug anyway. But days later nothing changed, and we stopped talking again. Then a few weeks ago, we got arranged alphabetically for Ring Day and he wond up sitting next to me. He spoke to me like we never stopped being friends and like nothing ever happend. We were laughing and were comfortable around eachother like always. He even told me I was "lookin good" and called me baby. But like all those other times, we stopped talking again after that night. Now today I was leaving the school when he was coming back inside when i heard him call my name from across the yard. I smiled at him and then he yelled back "what? you dont talk to me anymore?" and i yelled back at him "You dont talk to me!" and he laughed and yelled back at me "I dont talk to anyone". So thats the short version of the story believe it or not. I dont know what to do. The year is ending and I want to leave talking to him. I want things to be good again. I really do love him after everything. He has a gf now, but I dont even care about going out with him even though i want to. I just want us to be friends again. I dont know what I should do. I dont know what hes thinking. I was planning on giving him a letter at the end of the year explaining how i feel but now idk. Maybe i should just talk to him? But what do I say? He drives me crazy. But he made me so happy when we were friends, and I just want that again. I love him. The problem with talking about what happend with us is that everytime we start talking, he acts like there was never a problem and Im happy with him again and I dont want to ruin it by bringing up problems. But th