Still in love with my ex-teacher

Hey guys! Probably you're sick and tired of all the "little girl loves her 'perfect' teacher"-threads. Usually, these are phases. They get over sooner or later.
I hoped so, too. I hoped this for the last 3 years. But its still not over, it follows me everywhere I go and I wish I could set myself free, but i can't.

I got to know him when I changed schools and he became one of my new teachers. I don't know what I thought about him in the first lessons, probably that he's kind of refreshing. Nothing more.
Time passed by and we got to know each other better and better. We talked about theatre, literature, daily stuff, etc.
I began to look forward to see him in school. When I remembered one of the jokes, only the two of us understood, I had to laugh. I didn't wanted it to be true, that after half a year I was completely and absolutely fallen in love with him. I had never been one of the "My teacher is soooooo cute"-kind of girls. I was used to make sarcastic comments on statements like that.
Years before we met, I had my first boyfriend. Even on the new school there was a guy, who I really thought was nice. But it would be ridiculous to compare these things to my feelings for my ex-teacher.
Is it just this pathetic human thing, that we desperately want the people we can't have?

I tried all the time to start new, I even had a short relationship in these 3 years. Now we're done at school, but as I told you before - I'm not over it. Of course I would never ever ever tell him about my feelings - he's married, has beautiful children, hasn't feelings for me. Maybe I should add that he is not one of these PE teachers, who are seen as attractive by half of the girls in school, especially in 9th grade? In fact, most of my class thought he was mean and conceited and didn't like him from the very first second.

How to move on? How to forget a person you love?
I am out of school, and it says "Out of sight, out of mind". Why doesn't it work for me?

If anyone has any methods to get over it, please tell me.
P.S. I know he will never love me back, I know I have to get him out of my messed up mind. My question is only HOW.

Thanks for reading!