I have seen this a lot over the years, I hate weddings and stag parties so rarely go, but I have had so called friends stop talking to me for not going.
I still keep in touch with them and meet up with them etc give a good wedding gift but they cant seem to understand that everyone if different and some people just don't like stag parties and weddings and cut contact over it.
Im not going to change though, life is too short to go to events that you don't want to go to.