ltaylor, I understand everything you said. If my ex or my WH needed me to take care of them, I would be there in a second. They know that. But what your WS has right now is contagious - to you. Everything that is wrong in his life is your fault, and nothing you say will change that - while he feels this way. What it will do is drag you down mentally and physically until you aren't in shape to take care of yourself or anybody else. Going dark with my husband is what enabled me to stay sane, and I feel better now than I have in a very long time, even before the split.
Sometimes, support has to be from the sidelines, not on the gamefield.