I had the same problem I started to fancy my first crush in year 8 I started dating other guys but, I could never tell him how I felt. We were best friends joined at the hip and all our friends knew I liked him. Got to year 12 and I thought screw it and finally told him. He actually felt the same way but, we only lasted 2 months. From where we were best friends I couldn’t make the transition over to a relationship it just wasn’t right and he was so nervous around me romantically it drove me insane. We broke up, he had a best friend that was similar so thought that would work. He was also clingy and it drove me mad so I broke up with him and everyone went off to uni. And he got with an old best friend of mine they went to the same uni and I had to hang out with them for 4 years. I couldn’t get away from them. Just watched them hurt each other, had to convince him to stay with her and not leave her for me because they lived together and deal with him trying to cheat with me when he got drunk. It was so painful and not fair on any of my boyfriends. Eventually they broke up and I got with him. There was so much hype and expectation and he did not live up to it, I was disappointed. I thought it was a fluke but, no it just wasn’t right.
Eventually I distanced myself and walked away from that group of friends I haven’t spoken to any of them for a year now and I can honestly say its the best thing I have ever done. Without him around I have been able to move on and find a successful relationship.
I guess what I am trying to say is you will never forget about him he doesn’t sound like a crush he sounds like your first love. But, you need to distance yourself so you can move on and be happy. Trust me on this as much as you tell yourself you can be friends you can’t. Walking away from him and all our mutual friends after 10 years of friendship was so lonely but, the best choice I ever made and I have never been happier.