Wedding date!

Me and my SO have been together for a little over 2 months. Been talking all together for 4 months. We are currently living together. I'm always around his family. Well his brother is getting married in October and I want to go but at the same time I don't because he's gonna be busy doing wedding stuff and I'll just kind of feel left out. But I know he will be upset if I don't go. So do I go or no? Opinions please.