How do I get over a guy??

So I’m gonna start off by saying that I‘ve always had attachment issues.

I’ve had this thing for a guy for a while now but I’ve had my chances and blew them😩 We’re still good friends and tbh i feel like there’s still something there but I really don’t want to keep thinking about him and have this thing for him when I already know that i cant have him. I’m scared for the day that he’ll find someone else if I still have something for him because it’ll break my heart (it’s happened to me in the past with two other guys that I had really strong feelings before and it honestly affected me so much emotionally and mentally)

Besides blocking/deleting him, what are things that I can do to help me move on?