I have always been curious about this. Does it turn you on watch someone get off looking at your wife? No judgment whatsoever, just curious.
We met a couple at Hedonism II in Jamaica who were relatively new to the life and the wife found out the husbands kink after caught her husband watching sex videos they had made together with a complete stranger. The husband was watching the guy jerk off and the guy was looking at the wife on video. She got pissed off and started blowing the guy and her husband came all over the place.