Why does the man who says he loves me, want nothing to do with me??? He even blocked me off of Instagram!!!?

I met this guy at a university play & we were both acting together as husband and wife! Eventually we begun to have interest in eachother, but I made the first move.I was 19, he was 27.I moved to USA to study for 6 months from UK & he was from USA.I would spend most of my time with him at his place, getting quite intimate.I told him that I was seeing other people cause we're not even dating & he was very put off with that! We would have some frequent arguments cause I felt like he wasn't sure whether he wanted me & once he said he was never attracted to me. one day out of the blue, he said he wanted to give me his heart.I said I love you as a friend. He would keep on saying to me that when I leave USA, I'm gonna forget about him & tell my friends that I had an unserious fling with an American guy.I kept on saying no!We had an argument once & i ignored his messages for a while, but he was eager to surprise me for my birthday with an expensive dinner. I've caught him staring at me adoringly whilst I was sleeping like his in a trance.He would tell people that were in a relationship. But when I return to England, he never even calls me and his messages are stiff.Then I find out he deleted all our pictures on social media & unfollowed me & he never talks to me- it's been 3 months! I called him out on it & I said goodbye forever & he said goodbye, without no explanation.Whats going on?I really like him & don't understand where this came from! I just want to be friends at least.