Is it normal that i can't stop loving him?

Back in middle school I fell in love with my best friend. We had a short-yet-sweet/fun kind of dating experience that lasted a year and 2 months, but a lot of things were weighing heavily on my mind. My friends hated him, his friends hated me, we lived on opposite sides of the river that divided my hometown (neither of us had cars), and we were from different worlds skin color wise as well. So since the world was so against us, I decided to break it off with him. I loved him so much and only wanted him to have an easy & happy life...even if it didn't involve me. I was so mean to him during the first month of the breakup that he started to resent me, but we stayed in touch. Eventually, he moved back to his home town, 2 hours away, leaving me alone and depressed. Everyday we talked over the phone though. He would tell me of how his life was changing for the better, but my life was at a stand still. He's had a few different girls here and there, whereas I've dated no one. After high school, he asked me to move to his town so we could hang like the old days. Then he and I decided to move into an apartment together, along with his current girlfriend and her best (female) friend. It's torture seeing the two of them together, but I'm also happy that he's happy. We've had a few quick romps here and there between the time we split and now, and I feel bad for going behind all his girlfriends' backs and all, but when we're together I always feel so...I don't even know. He was my dream guy, and I couldn't make him happy, nor can I get over him. Is it normal to want to be with someone so bad, but keep your distance because you know he's better off without you?