So, my sister's fiancé was first my boyfriend. She introduced us to each other when they were "friends"(or so I thought). So he took a liking to me right away and we started dating for about three months. Obviously, I was young and dumb so I thought I was in love with him and would never want anyone else. Turns out, that he had been cheating on me the WHOLE FUCKING time with my Goddamned SISTER! My sister and I have always been close, I don't know why she would have ever done this to me!

And guess what? They're ENGAGED now, just recently actually. And he wants to get married as quick as next month. THEY HAVENT EVEN PLANNED ANYTHING YET. They're both so fucking stupid.

Anyways, since she is my sister and we've been "close" our whole life, she asked me to be her Maid Of Honor.

Am I wrong if I don't support their marriage and don't want to be her Maid of Honor? I mean,they both willingly cheated on me.

Update: Yes, my parents are very upset too but they said, "if your sister wants to marry a cheater, then she'll have to deal with that herself."