I find it interesting how PP framed it: She doesn't believe in a divorce

I don't think it's something you believe or don't believe in. It's an option you have. You either take it or you don't, depending on the circumstances and personal preference.
OP, I am probably a bit younger than you are, but I'm in the camp with the folks who say marriage is overrated. Especially after so many years and raising children. Frankly, I don't aspire to get close to my husband. But I value his companionship, and I know life with someone is easier for me than life alone. I'm not up to trying to find a replacement, because the very thought of having to get used to living with someone else is tiring. I'm not opposed to affairs on both sides, but so far no takers
