Friend backing out of wedding

So there is a lot of history with our friendship, we’ll call him “Brad”. We are the type of friends that don’t talk every day but when we do it’s like no time has passed. We haven’t lived in the same state in about 4 years but the friendship has lasted during that time and we are “that person” the other calls when they just need a smile or to talk something out. When I got engaged he was one of the people I called to tell and I later asked if he would stand next to me and he was so excited.


Fast forward 6 months. Brad is still friends with my ex since they live in the same town and he mentioned my wedding and being my best man one night to the ex. My ex freaked out and got mad and didn’t talk to Brad for 3 weeks over it. (Note: ex went legit missing for 2 weeks when he found out I was dating again but has since starting dating Brad’s ex.) So now Brad said he doesn’t feel ok being my best man or even attending as a guest because he’s worried about how my ex will react and it will affect their friendship.

I totally get that I’m not around anymore so their friendship has grown and I support that. But I’ve known Brad for years longer and it hurts that because my ex wants to throw a hissy fit I’m losing out on having one of my oldest friends attend my wedding. I was super understanding on the phone with Brad because I could tell it was hard for him to tell me but I’m pretty hurt.
Am I in the wrong for being upset? Is there anything I can do? (Part of me wants to text my ex and tell him to get he **** over it - especially since he has the new girlfriend - but I know I can’t)