My brother is getting married out of state. My whole family is travelling to be in attendance. My boyfriend and I are planning on going. The issue is that my brother is good friends with my ex-husband (that is actually how I met my ex). I just found out that my ex is travelling out of state to attend this wedding too. I find this an extremely awkward situation that he will be at a family function when he is no longer part of the family, especially being that he is travelling out of state to attend. I feel bad for putting my boyfriend in this situation and I also worry that some sort of drama will unfold because my ex has never met my boyfriend, but has made it pretty clear that he is very bitter that I started seeing someone so soon after we separated. We have been divorced for a year and separated for 2 years now. I can't not go to my brothers wedding, but I'm not going to tell my brother who to or not to invite. I'm also not going to disinvite my boyfriend! Should I just go and hope for the best?

Just go... keep your distance and hope for the best. I've seen many cases where ex's have maintained contact with ex-inlaws they are close to.

Yes, you really have no choice but to go and make the best of the situation. Perhaps your brother can mention to his friend that you are coming with your new boyfriend so that he has a heads-up and is not blindsighted.