For me, I think two stages of humiliation: those guys with a big age difference from my ex. So a teenager when she was in her late twenties, and a guy about 45 when she was 25. But the humiliation on top of that is when I later met one of these, the older guy who was in her line of work. We were invited to diner at his house; I know nothing about his having made a cuckold of me at the time. But when I later put the evidence together, and admitted it to myself, wow what a humiliation (and turn-on).