My sister is getting married next month, and I was so excited to celebrate with her. I RSVP’d with my partner of three years, someone who my family knows well and has always treated like one of their own.

Everything was fine until last week, when my sister called me out of the blue and told me she had to “adjust the guest list.” She claimed it was due to budget issues and said only immediate family and spouses were allowed—meaning my partner was uninvited. I was disappointed but tried to understand.

Then came the bombshell. I was scrolling through Instagram when I stumbled upon a story posted by one of her bridesmaids. It showed the bridal party joking about how my sister's fiancé had pressured her to uninvite my partner because he found them “annoying and distracting” at past gatherings. I couldn’t believe it—this had nothing to do with money and everything to do with my sister’s fiancé not liking my partner!

When I confronted my sister, she admitted the truth but begged me to come anyway, saying she couldn’t let her fiancé get upset before the wedding. I told her that if my partner wasn’t welcome, neither was I. She exploded, calling me selfish and accusing me of ruining her special day. Now my parents are furious, saying I need to “just go and support her.” Meanwhile, my partner feels guilty and says I should attend for the sake of family peace.

So, AITAH for refusing to go after finding out the real reason behind her betrayal?