Need to desperately get over my childhood sweet heart.?

[Kay Sweet]

Any tips? I knew him from when we was 3 till 8 then he moved away saw him few times after, the feelings never went. Now hes in a non serious relationship. And I really need to forget. He never talks to me though I did have him on fb before my ex made me delete him. I have tried loads to get him out my mind but nothing works. I follow him on twitter but that's about the only contact I have with him, he never blocks me or sends me any nasty messages. Hes been with this young woman for about 4 months. But I have heard its not serious, he hasn't even had any pictures with her, invites her round. Or goes to places with her. Despite this I still need to forget him for good, hes always in my head, and how can I one day find a new relationship when I can never get "him" out of my head. Any useful tips??