Yesterday my sister got married to the man that she has been with for 7 years, though they are fairly young: only 23. She is my older sister, and I've always looked up to her and have felt great pride in their relationship; my dad is emotionally abusive to my mother, so it gave me hope that I could develop a healthy relationship too despite my upbringing.

During the wedding, I danced with and ended up kissing one of the groomsmen, the husband's best friend. My sister got upset, and she told me it was because she used to like him and it felt like incest. I said I would avoid him the rest of the night, not really understanding what she meant. Her husband told me she had been fearing that this groomsman would hit on me and that she had done "stuff" with him before. When I said "before you got together?" her husband told me an ugly secret, and my sister doesn't know that I know.

Apparently they have had an open relationship for years now. She is now so furious with the groomsman for making a move on me, that she will never do anything with him again, according to her husband (obviously she has feelings for him... how can she feel okay about this on her wedding day?). I feel absolutely SICK. This has come as an incredible shock. I really don't know how to come to terms with this. I thought for sure their marriage would last forever. Now I wonder why in the world they even bothered to get married if they aren't going to be committed to each other fully. My sister has always been my best friend, but now I'm not sure I want to be anymore. This incident is of course still fresh- it's only been one day. I can't help crying when I think about it. I just sent her off with a Maid of Honor speech about how much I believed in the two of them. Now I'm just pissed at both of them. I feel betrayed, fooled, naive, disappointed, and angry. How could she? And how could he? I thought my sister had morals. I don't know if I can respect her now, and this is a BIG deal for me to be saying this. I've always held the highest opinion of her, and am blindsided by this information.