Disagree. If it was innocent there would be no secrets and he wouldn’t ever call it “an affair” and then say he was naive. Nope.Not complicated at all. Wife's dad passed just before his did. They were both grieving. He started on a bereavement site for people who lost a parent or some such. Like an alcoholic going to AA. He made friends with a woman there who had lost someone. When they were down, they would meet and talk about it.
His mistake was befriending a woman and not a guy to talk to when he was down. When woman started wanting to meet in private location and started flirting, he saw that she had other motives, so he distanced himself from her.
In mean time wife handles her bereavement and finding out hubby is confiding in a woman he met from a bereavement group by screwing old friend. And is refusing to discuss her adultrous sexcapades.
Sounds pretty simple to me. She is for the streets.
ETA they are both for the streets. IMO.