missing my ex

I thought that I could get over him and I thought that I was but then as I was thinking for a while and realised that I'm not interested in anyone else only him. but.. he has a girlfriend so I don't really have a choice but to get over him and It's gonna be really hard but its something I have to do. It's so difficult because I see him most of the time at college and all we share is awkward eye contact and i miss what we used to have and the memories are getting to me.