My ex is getting married

So my ex is getting married this year, and I'm still hung up on him. It's been two years and I've only seen him once in that time, and it was when I went to a party and he didn't know I was going to be there(we have mutual friends) he was all happy to announce his engagement until he saw me, he acted so weird like I though he was going to cry. His fiancé was knew something was up and kept asking what was wrong then they left.. It's just weird to me because he broke up with me...