I need to start this by saying that I never thought in a million years I would ever be close to my middle sister. Not to go into too much detail but her father is not my biological father and there is a 10 year age gap between us, that coupled with my resentment towards her father and other things led to us having a very difficult relationship. However fast forward to her turning 17, getting her license, and just wanting to be away from our mom for a night led to her and I bonding. Now she is as close to me as we are to our mother.
So with that in mind I had for quite some time intended to have my best friend as my MOH. Her husband, though he is one my FI's best friends, is not the Best Man. I knew she felt awkward about not being paired with her husband. Then after a conversation with both my sisters I found out that the youngest did not want the MOH title, and would not be hurt or upset if I chose our sister as MOH.
I thought "problem solved", I give my sister, who as I said I had become very close to, a special honor, and my best friend gets to be paired with her husband.
My best friend decided to take this as a demotion and proceeded to remind me every time wedding stuff came up that it was Sarah's (my sister) job now.
Now that the wedding planning is in full swing, deposits have been made, the date it set, suddenly she is changing her tune.
She tells me to my face that she is just a bidesmaid and will do whatever the MOH and my mother tell her to do. But to the rest of the bridal party she (according to them) inserts herself into everything, has tried to actually start planing the shower without talking to the MOH first, and goodness knows what else.
I should also mention, and I apologize for rambling, my mother does not very much care for my best friend. She and I have had some rough spots in the past, but I love her and couldn't imagine not being friends with her.
How do I defuse what I feel is a ticking time bomb. I want my best friend to feel like she gets to participate. But I am so incredibly close to my family that I don't want to take anything away from them.