A bit of a back story here... my sister has a boyfriend since...about 9 months on and off ? Over the course of their "relationship", they broke up 2-3 times because He really was shitty to her and he made decisions that were truly far from her values but she decided to act like it never happened I guess and went back again... Anyhow...He disrespected her multiple times and she told me stuff that I can't forget nor forgive he did so I have no contact with her when he's at her place. Fast forward..my Fiance and I are getting married and she (my sister) is performing the celebration. We are doing a micro wedding and we did not invite said boyfriend...when I told her he was not invited she was supporting of my choice saying it was my wedding and I could have who I wanted there. Keep in mind that no one in the family is supportive of their relationship and for that reason...she hid the fact that they were back together again at first. Another fast forward to yesterday...we are 4 months before the wedding and my sister ranted at our mom about how I was being disrespectful of her, her choices and that if she wasn't the one doing the celebration, she would not come. She of course, did not tell me this and I wouldn't know if my mom didn't tell me.

So... AITAH for not inviting the boyfriend to our micro wedding? She told our mom that she would not have brought him because of the situation but the fact I did not invite him is what doesn't sit right with her.

Another bit of back story..she (my sister) started dating him right after getting out of an abusive relationship so she jumped right in another abusive relationship and we are sad and scared that she is accepting those situations. we almost did an intervention HIMYM style.....

EDIT: to had that the timing is not part of the none invitation - only his behavior.

EDIT #2: do you guys think I should just invite him and hope he will not come ? And if he does... Suck it up because I love my sister and ultimately it's more important that she's there with all her heart than with a grudge ?

Help me with some perspective please