It was cool to be honest with my wife. We talked more at some length and I let her read the thread. I think she has a good grip on things. She told me the sex wasn't related to S; which really puts my mind at ease.
It turns out C had had some of these thoughts before, too, and had not felt comfortable discussing them, for basically the same reason. It's so awesome to just be able to be honest and candid with my partner, I think things can only get better now.
Regarding S, I think all the advice I've gotten has been so helpful. If I'm being honest, I didn't expect everyone to be so caring and worried about her. Kind of eye opening, refreshing. Anyways, it's all out in the open now...time to just see where things go!