I reading posts from wayward spouses on other forums, the waywards who did this, almost to a person, said they did not even think about it when they invited the AP into their bedroom. They were so caught up in the affair that they did not give one smidgen of thought to how it would affect their spouse by doing this.
So again, it is not so much that they are out to deliberately humiliate the BS, but that the BS factors not at all in the compartmentalized thinking that goes into conducting an affair.
I agree with this. That said, I have to imagine that cheaters, being individuals, may have an number of reasons they do things like bring the AP into the marital bed. For some of them, it probably is a fvck you to their spouse. Some probably do want to get caught, so as to end the marriage they otherwise lack the nerve to end on their own.
My ex-husband was a serial cheater, and as such was one of those to was exceptionally good at compartmentalizing, so his motivations would fall more in line with bandit's comment. I don't know if he did or did not ever bring anyone into our bed. It's possible. But even if he did, as with so many things in his life, it more than likely wouldn't have been about me or our marriage in any way. He had the spooky ability to completely separate his affairs from his marriage. They just didn't even exist in the same universe. So, he wouldn't have been trying to say fvck you by brining someone into our bed. Nor would he have been trying to get caught. Rather, his musings wouldn't have had anything to do, at all, in any way, with me or our marriage. Nope. It just would have been something he didn't give a second thought. It was his house and his bed, so where else would he have sex?
I strongly suspect his thinking worked that way, because I found out during the divorce process that he'd more than once over the years loaned our home to one of his buddies while we were out of town. So his married buddy could have a nice comfortable place to spend time with his AP. When confronted with that information, he was honestly baffled as to why I might consider that a problem. Why wouldn't you let a good friend stay in your house for a couple days, especially if you were going to be out of town yourself? If it didn't occur to him that allowing another adulterous couple to use our bed might be super skeevy, I'm guessing it wouldn't have occurred to him to think twice about using it for his own trysts.