Hi. I have never attended any activity that involved an ex. It's just too awkward and uncomfortable to even think about.
I'm not hung up on any of my ex's so I wouldn't care about their weddings one way or another. I don't consider any of them the one that got away.
I am only friends with one of my ex boyfriends who is already married and I like his wife and they have the most adorable daughter. They are a very good match. I like being his friend and have no desire to ever be involved with him relationship wise so his marriage is not an issue for me.
As for all of my other ex's, there is a reason why I don't talk to them anymore. It's because I dislike them very much and I don't care whether they get married or not or whatever they do. I wouldn't want to go to any of their weddings just because I dislike them so much and it would be so boring for me. And actually, better for them to be married because then I don't ever have to worry about them re-appearing in my life again looking for a second chance that will never happen, even if he'll froze over.