Do Polish married people cannot stand up in other people's weddings?

hello i am getting married in oct and my best man backed out because he is getting married in aug and his fiance is 100% polish she said in polish culture or some thing married people can not stand up in other peoples weddings.. is this true>? or is she just trying to be a butt head:??? please help!!!

you mean be grooms?

yes he is a groomsmen but he is not polish his future wife is

If the wedding is Catholic it's all the same apart from some traditional toasts or music, non important stuff like that.

It's an old, old backwards Polish belief that a married bridesmaid will bring bad luck. Many Poles don't believe in this but there are a few that believe in such nonsense. Anyone can stand up for a wedding.