hit submit before ready, sorry. True story . . . I had a massive crush on a guy my sophomore and junior year of high school. Oh, I really thought about him 24/7. lol I was so into him. He flirted back. We did not date or anything. Years later when I was a senior in college, we ran into each other. I was like "holy cow" and we went on one date. I was so bored and not into him after an hour that it was hilarious to me that I'd spent SO much time and energy thinking about him. So, crush interaction often doesn't tell the whole picture of someone. good luck
Sorry, I think I missed this post a while back and believe it or not, just saw it! So, the thing about crushes are that they are rarely based in true reality. He probably got a girlfriend closer to his age or decided it was silly to mess around with someone so much younger and in a different part of their life (he's been married already, is a father, etc. ). I would not take it personally. Crushes are just an attraction of some sort. They are often just one way but this sounds mutual. However, it is what it is. You miss it perhaps because there is no one else you are dating or having an infatuation with right now.