I have a bridesmaid who I've known since high school, however over the past few years we have grown apart. We don't see each other except for every 3-6 months (I've seen her once since being engaged) and talk only occasionaly. She became very upset when I told her I chose someone else to be my MOH. Not only are we not as close as my MOH and I are now, she does not have the time to be at any of the things I need help with, in fact I've had to reschedule bridesmaids dress shopping three times for her schedule. She confronted me about the way I asked her to be a bridesmaid (apparently I should have taken her out to lunch and told her how amazing of a friend she was, instead of just asking her, face-to-face the way I did).
I also have been receiving passive aggressive comments from her about my MOH choice.
I would have put up with all of this, it meant a lot to have her in my wedding, but recently I received a copy of messages from her to a mutual friend saying that I was overweight, my wedding dress made me look like I was pregnant, my Fiance treated me horrible and has cheated on me a few times, and that the two of us are pigs who don't clean anything. She also said that she does not want to be in the wedding but doesn't know how to tell me... These are all fabrications (except for the weight thing, and as everyone knows...you never tell a bride she is fat! 
). What I'm asking for is some advice on how to ask her to leave my bridal party.
I do not want to overreact, I do not want to cause a scene, but I just feel like I cannot have someone like this in my wedding, especially trash talking my fiance. Does anyone have any ideas on how to help me?