Having been the person who was relying on someone to be honest and faithful with me, and finding out they hadn't been, I know how that feels. But even before I experienced that particular type of betrayal myself, I've always had enough empathy for other people- even strangers I've never met- to know that I didn't want to do anything to hurt them if I could avoid it.
When I was nineteen, a friend of mine who was going out with a girl I didn't know- approached me sexually. My immediate response was, "Why would I want to do anything to hurt that girl that I don't even know?"? It didn't matter to me that he
was willing to do something to hurt her- I made my own decision that I didn't want to do something to hurt her. And having sex with him, would have been hurtful to her.
Besides the fact that if you know someone's married, and you know they're willing to betray someone they made a vow to and don't have the courage to be honest with- what kind of relationship will that provide for you? Can you really ever relax and enjoy your time together?
I think both people who are involved in a betrayal of someone else are being selfish- putting their feelings and needs before the feelings and needs of at least one other person, and sometime children as well.
Ah but if you were a bored middle-aged man, stuck in blasé, missionary-position-once-a-month 30 year marriage with a fat argumentative indifferent wife, and you had a sexy young hot co-worker why took great pains to seduce you just so, then the question become a little more open ended.
If loving you is wrong...
I don't want to be right
If being right means living without you
I'd rather live wrong than right
Yeah, that or you could just be honest. Get yourself unstuck- and maybe unstick the poor wife at the same time-why not do everyone a favor...