Clothing was moved around and the genitals of two people who were married to other people were rubbed together.
Do their using some strange exotic technique change the "married to other people" part? Does it change the fact that one of those "other people" was his subordinate? Which moves it from the "not right" to "down right reprehensible".
So, if one person cheats first and the marriage is broken, the other just has to take it?
(For clarification, I don’t believe that Charles ‘cheated’ first. Diana was as good at PR as Harry’s wife is now - though in her somewhat hysterical way Diana was a lot smarter about a lot of things.)