How about a married person who carries on an affair with someone else?? After all, Diana wasn't so "good" in that respect--she was still married to Charles when she was having an affair (publicly acknowledged after a time) with the riding instructor fellow, whatever his name was.
In truth that incident at the races was just one thing out of many that made me unimpressed with Diana. There were plenty more actions that made her unlikable for me. IMO she was a twit. Charles—I had no use for him long before he met Diana—that stems from something that he did when he was here on a Royal visit years ago, something that I have absolutely no use for-—and as for Charles’ affair with Camilla while he was still married to Diana, that is kind of counterbalanced by her own similar behavior. She blamed Charles for the breakup of the marriage; Charles blamed Diana for the break up...I have little use for either side and when it comes down to it, for me Camilla is probably the least irritating of the whole lot!