What you are telling us, amidst some other things, is that you were not happy with him for at least the last year you were together and you are not happy without him for the year since you broke up. It's not essential that you get "over him" but it is essential that you focus on utilizing your talents and intelligence towards producing something in your life that positively affects others. Art, music, literature, gardening, theatre, science.... something. Something that will lift you entirely out of the cycle of unhappiness that you have been embracing.
The chances are excellent that the romance you two shared will not be, for either of you, the love of your lives. And he may be dealing with his aftermath differently than you are. Of course you want both of you to be happy! It sounds like, for him, that happiness need entail you being in his past.
Neither of you need attend the other's wedding to the person who will make a life partner. Letting go doesn't mean you "get over", just that you let go of expectations. Like how happy you'll be to run into each other. Let that go.