Would you be upset if your BM did this? (kinda long)

I sorta have two MOHs. My 2nd MOH just told me she is not coming to the Bachelorette Party because she knows that it will upset her BF because part of the plan includes going to a club.

Now, there's alot more to this story than I can ever write in a post, but suffice it to say that this boyfriend of hers is manipulating, controlling, hurtful, and borderline mentally abusive to her. No one in the family (she is my cousin) can stand her being with him, no one likes, him - not even her friends or her mom. She is not even herself when she is with him, she is always miserable but she is head over heels in love and is completely blind.

She has been a GHOST during this entire wedding planning. I don't expect her to be up my a s s with wedding stuff, but even a phone call that is not for the sole purpose of doing her a computer favor for her BF would have been nice during this past year.

I am so upset because she is so manipulated and my miss my REAL friend. We've already discussed her change in behavior with him and it's no use.... she claims she 'likes herself better this way'.... being a mental slave to him! I've never seen anyone become so brainwashed by another person in my entire life. Anyway.... the worst part is -- she didn't even TRY to discuss the BP with him. She's too worried that it will upset him so she won't even bring it up!!! That part infuriates me!!

I know that going clubbing is not everybody's thing, but hey, I'm only get married once and we aren't even having strippers!! I can't believe that she won't even TRY.

FH is livid and really really REALLY wants me to 'demote' her. He says that he just wouldn't feel right having her stand up as a MOH after all this crap. He says he can't even stand looking at her. It's funny because in the email she wrote me to break the news, she said that she's worried about the consequences going to a club would have on her RELATIONSHIP with her BF.... obviously, she could give two sh!ts about the consequences her behavior is having on OUR FRIENDSHIP.

I don't know what to do.... one my other BMs has been soooo wonderful through all this... I would really rather have HER as my other MOH at this point... I don't know if I can bring myself to do that ... or even if it's the right thing to do. I feel like I am always letting my friends walk all over me in ways like this and if she felt that her doing this would hurt our friendship, maybe she wouldn't do it... but obviously she thinks there are no consequences to screwing ME over, there never have been. I don't know what I'm saying anymore... I'm rambling so I'll stop but tell me what you would do in this situation???