Between a Rock and a Hard Place

I know many people love being in this place (hahaha)!!!!  So the joys of planning a wedding have completely gone out the window. We are having issues with some people who are supposed to be close friends. I am feeling completely stuck right now (damned if I do, damned if I don't)  I am stuck in a place someone very selfish has now put me in. I have to choose between something I so strongly believe in and honestly don't want to back down on and hoping B doesn't regret me later for it or throwing what I believe out the window. I am at a loss of what to do. It makes me sad that a person who is supposed to be a big role in my love's life is choosing not to be there. It is an impossibly hard decision to make. And normally I wouldn't hesitate to stick to my guns, but the idea of having him resent me is killing me inside. :/ hoping one side becomes softer.