I feel for you. I was extremly close with my MIL and FIl and losing them as well as my wife is hurting. I cant imagine them welcoming OM into the family.
Steve is right. I'm in the same boat as you with needing to drop all expectations. Expect nothing Gigi. Expect that you will no longer have affiliation with your in laws and you will create a new life for yourself where you WILL be happy.
If we end up divorced then we can't expect to still remain close with their families. It is their families. I know my MIL is heartbroken over this whole thing but blood is thicker than water and will stick by her daughter which means not carrying on a relationship with her ex after Divorce. I expect nothing from them.
I'm really sorry you're dealing with that Gigi. I know how much it hurts. I hope you're doing okay.