Don't go. Everyone else's life is more important than anyone who might be getting married.
My sister told me she was getting married on during the European Juggling Convention, the biggest juggling event of the year. I told her I might not make it to the wedding, especially because I'd missed the convention previously due to my brother getting married. In the end she changed the date of her wedding because it was bad for other people too.
I've now been to 16 European Juggling Convnetions in a row.
Also I had a friend who missed half an EJC to go to a wedding, and she told me it was one of her biggest regrets. She thought she was really good friends with the couple and it would be special day for them all, but it wasn't. It was just a special day for the couple. For her, she hardly spoke to them, except a few words. She didn't eat with them at either the breakfast or the main reception, as only family was allowed at the head table. And due to assigned seating, and as she was single, she was put on a table with people she didn't even know, rather than a table with other friends, due to them being couples.
Treat your friends wedding as them putting on a first gig of a cover band, but a vanity project where the costs are covered by a private backer, and it's an only gig so they aren't out to win fans. They are going to pretend to be rock stars, and ignore or not have time for anyone who isn't in the band. This might be a fun event, but would you miss the main vacation trip of your year for it?
The better the friend they are, the more they will understand you missing their wedding.