We know S can justify things any way they want, the bottom line is they know it's wrong and have to paint something over it to make it right. For your sake I would say, do what we have learned here. Do the right things for the right reasons. Then when all is said and done we walk away knowing we did what was right to the best of our abilities.
Hopefully the events that you have related will sink in and H will start to come around. From my perspective let me say this. I have in the last couple of years ran into a few old High School flames. All though it was great to hear how much I had meant to them, I did not see any way that could justify having anything more than a distant friendship with them. I respected both mine and their families and I knew I was a better person than that. No matter how old we get, sometimes we are just selfish. But I see myself as a better person than that. If our spouses can just get over these selfish phases, they should come around. Our challenge is to treat them with love now.
(Regardless of how much you want to kill them now).