in need of opinions

So this is going to be a long topic, Back in the summer of 2013 I was becoming a senior in high school and I met a Junior at a different high school in my town, We became friends and out of the blue to kissed me one day, O was confused by it. I slowly caught myself catching feelings but he never really told me what he was feeling... we ignored it and continued on as friends... this happened over a few months... in the middle of my senior year he dated some girl from his high school, I was upset but never told him, I was upset because a little before that I confessed to him that I liked him, but I would always show it since the kiss. He continued to date her and then The my broke up, afterwards we began to hang out again as friends.. then one day he mentioned he was going to ask some girl he didn't really know to their prom.. so my thoughts were is he trying to get at her? Why would he take some girl he doesn't know all that well? It bugged me. They went I kept my distance but I had a feeling that they were "talking" ... so afterwards he said it didn't work out, and again we began to hang out but this time we messed around at his house, At the time a guy from a different town was trying to talk to me and I gave in to the talking but when "my friend" invited me over I thought maybe he just wants Sex... well we didn't communicate that night about what was going to go from there.. that same night I left my phone in his room because I slept over, that guy from a different town texted me flirty, my friend seen it but I had no idea I just noticed that he was like cold with me the rest of the night, over the next few days I asked him why he was cold with me and he said he had seen it, He said I lost his trust... we stopped talking and then about about a year later he apologized saying he knew I was a great girl and he screwed it up, I forgave him and we continued as friends recently he flirted we met up made out and I stoped him and gave him an ultimatum I asked him your in or your out no in between I'm not going to be a friends with benefits.. he asked for some days and I have it to him, But he's still cold with me... he says I play too much... I don't know what to do... help please!!!!