So, Xmas of 2017 my brother in law and I got into a huge fight. He has always been kind of a dick to me but this specific time was my tipping point. We were all drinking, having fun. HE brings up race/white privilege and I welcome the discussion because as a grad student in cultural studies, I study/talk about this shit all the time. Fine. He fancies himself the “devils advocate” in any and all situations. Things get intense and just in time, a friend shows up and he has to get up to grab the door. As he does so, he makes some drunken comment to his friend about me along the lines of “She always says stupid shit and pretends to know what she’s saying” when asked about why we were shouting as they approached the door. This does it for me and I tell him to fuck off, and I go to the guest room to cool off. 

I overhear him talking shit about me to his friend, talking about how “he didn’t even try that hard and my whole snowflake worldview came crashing down.” “He has to handle me with baby gloves,” etc. literally nobody else agrees with him, and I come out and mention that I don’t care about the discussion about race because I have them all the time...but I don’t appreciate being belittled. This makes him laugh and continue to be a dick, so I go back to the guest room and that was that. 

Now my question is not necessarily about him; most people agree that he’s an asshole...I am mainly concerned with my sister, who is frustrated because I’ve actively avoided him since this event. I understand that she doesn’t want to pick sides between her husband and her sister, and she is the type of person who just wants harmony with everyone. But her husband adds nothing to my life but frustration and I don’t feel like I owe her any more attempts to hang out with them both (this is not the first time he’s been rude to me/we’ve gotten in a big fight). 

So, two weeks ago we happened to be in Virginia at the same time randomly (we live in separate states.) she suggested they drive to where my partner and I were on a Sunday because her husband had the day off (he was there for work). I told her the truth, which was that my partner and I wanted alone time. She ended up coming on Monday alone, and she confronted me about why I have been avoiding her husband. When I told her I had no interest in being associated with him she got really upset, and I told her I’d try one more time to hang out with him. But I REALLY want to take that back now because just the thought of interacting with him again gives me anxiety. She wants to bring him to my graduation in May and I don’t want him there. 
AITA if I go back on my word?

Thanks in advance. 

