For now - follow your C despite what anyone else says. Your C will be a good judge of when/if to come clean and how much. There are times when I honestly think that if H was having an affair I wouldn't really want to know much about it - I would only want to know that it had stopped, that he was genuinely sorry and what steps he would take to have it not happen again. Other times I think the opposite. Who knows?
I hope you figure things out for the sake of your entire family.
