<human>: Can you summarize the given text in a few sentences?

When I was 14, I met this girl and we became very close friends. We ended up dating when I was 15, and we were together until I was 17. It was awesome being with her, and to spare details, I would say that we really helped eachother learn a lot about relationships and love. It wasn't a perfect relationship, as none are, and it wasn't like, a blind-love teenage honeymoon type thing. Anyway, she was a year ahead of me after a complicated summer, she chose to not continue our relationship going into college. Even though we were both broken up about this, I understood her reasoning. 

Throughout the next school year, me being a senior and her being a college freshman, we went through phases of talking and not talking. She told me it was very difficult and she still had feelings for me, and I told her the same. However, given the situation and the choices she made with not doing long distance, we both did date a little bit. I had brief things with three girls since my ex and I broke up. 

Now I'm 18, and she recently got into another committed relationship. I guess I'm confused if it's normal for me to still miss her, and if I have some sort of problem. Let me clarify, I don't have like, "break up blues", I just find myself missing her often. I don't miss what we had, because that time is gone, but I miss her as a person, and being somewhat friends is great, but tough. I've dated a few girls, like I said, briefly, but none of these circumstances went anywhere. Do I have a problem, still missing a girl about a year and a half later? I am open to dating anyone, but she's always a thought in the back of my mind. I would never do anything to harm her current relationship, because I believe that if both people treat the other with love and respect, they should be able to stay that way. 

I guess my question is, am I doing something wrong? Why is she still in my mind? Even after the break up blues, dating other people, and whatnot, she's still there.
<bot>: Dated a girl for 19 months, broke up circumstantially. A year and a half later after dating other people, I still miss her. She has a boyfriend now.