^^^ this is the kind of thing I was suggesting to tell her you are afraid it will come to if she continues to refuse to communicate. I was suggesting that, instead of dropping the bomb on her after you have convinced yourself that there is no hope (like my WAH did to me), that you open up to her about your fears and concerns about the affect on the marriage.
Don't make it all about sex... it is more than that. It is about two people being willing to support each other and solve problems together. It takes two people to make a marriage work. Does she want it to work?
My H waited until he felt totally hopeless before opening up to me. Don't do that to your W.