How do i stop thinking about my Ex?

I was with my ex boyfriend for over 7 years, im only in my early 20's so it was a big part of my life... i broke up with him because he wasn't a good boyfriend. He never did anything for me, i put all the effort into our relationship, he never told me i looked nice ever or anything even when i dressed up just for him to go out for a meal (that i obviously planned)... he just treated me like a friend towards the end of it, just became really complacent and too comfortable. But i loved him with every single bone in my body, as much as i love my own family and there was just no way i was giving what we had up, despite the constant dissapointment. Its not like he didnt love me, he did, i was the love of his life up till then and i know that for a fact. It was real what we had, so real. I dont know if ill ever feel that in love again. When i went to university, i knew that it would be a struggle for us to stay together because we'd grown up together but had become SUCH differnet people along the way. He was staying home to do a 3rd year in college (his course was 3 years) and i'd already graduated (mine was the standard 2 years). We broke up then and it was really hard for him, i know that, but he wasnt willing to change and i couldnt always compromise myself and just be grateful for what little time he did give me, i was always unhappy. We stayed in touch at least every week but soon i had another boyfriend, who made me feel special and i needed that so much. It upset my ex so much which i totally understand. That didnt last very long though, and i havent seen anyone since that. When i went home in the summer, we started seeing each other again, but he never looked at me the same as he did when we were together all those years. I know i ruined it by seeing someone else, broke his heart, but i couldnt just stay with him out of nostalgia or because it was comfortable... i loved him so much but that on its own just wasnt enough for me. After i went back to uni, he slept with a couple of girls which made me sad but obviously that was his choice, he didnt owe me anything by this point... This is like 9 months since we split. Now its well over a year, and he's honestly so over me and we dont even speak anymore but i STILL think about him every single day and i hate it! Why cant i just move on entirely? I know we're not meant for each other and we'll never get back together because neither of us would want that and he obviously doesnt have any feelings for me anymore after all these years :-( I just wish i could block him out of my head, it makes me so sad/ annoyed with myself. I really need some advice or guidence, anything you have to offer. I just dont know what to do...