One of my best friends recently became engaged to a horrible man.  He is not nice to her and not nice to her 4 year-old son.  I have voiced my concerns to her, which she heard but is still planning to go on with the wedding.  I realize that this is her choice and I will respect that, but should I be a bridesmaid at a wedding that I don't agree with?  My options are:
A) Be a bridesmaid under the knowledge that I am being supportive of HER and her needs as a bride.  This would be easy enough, although because he is a very controlling groom, I know I will have to personally deal with him during the planning/coordinating processes of the wedding.

 Decline, and explain that I don't feel right about standing up as a legal witness to something that I very much don't approve of.  While I would still like to attend the wedding, and continue to keep her as a friend, I'm am worried she will take this personally and end our friendship.
Thoughts!?