Why is my first true love avoiding me why won't he talk to me?

i am really concerned that my first true love is avoiding me,not talking to me and not seeing me anymore sometimes I see his friends from time to time but other than that I don't see him anymore I really need to talk to him but he won't listen to the words I say on Facebook, Facebook is the only way I can contact him I wanted to tell him that I'm sorry for whatever I done for him to stop talking to me and hope that we can be friends and if he has a girlfriend that I am OK with that relationship I do not want to lose our friendship I don't want to lose him please someomehelp me because I really miss him being his girlfriend if single and if in a relationship just friends no more than that thanks for anybodies advice, is this a bad sign ?