A little history here. She is a friend of ours (more his than mine) from college. Let's call her Sam. Now my fiancee's best man, Jake and her had been talking a bit a few years back but nothing came of it. Then Jake met Megan. 

Megan and Sam were friends for a long time, but only really talked when they weren't dating anyone. When Jake and Megan started dating and eventually married, Sam was furious. She still hates them both to this day. She claims Megan stole Jake from her. 

Sam can be pushy, judgmental, and condescending to people and I'm not sure if it's on purpose or if she's just clueless. I wonder why she's even his friend sometimes since from what he's said, she is exhausting to be around. 

Anyway, would I be an asshole to suggest that maybe she shouldn't attend? I'm too old for this high school crap that she doesn't seem to have grown out of. 

TL;DR: I want to not invite a friend to our wedding because she hates the best man and his wife. 