It’s hard to feel true remorse until the cheater has fully separated themselves from their lover
So depending on the circumstance, relationship “boundaries” and what constitutes “cheating” have never been fully agreed to or even discussed constitutes a real problem. People assume their partner knows what they consider to be “cheating” but sometimes they don’t. This is a discussion every couple should have early on. If you have different definitions of cheating, you could be headed to trouble. In these circumstances, the probably-cheating spouse will be very defensive and not agree with you that they cheated. And therefore, won’t show remorse. I think this is not the most common circumstance.
2. The Cheating Spouse is engaged in an “exit affair.” They used it to get out of their marriage. They have already decided the marriage is over and the affair was the method to do it – they found someone whom they wish to be with more than you, or have at least proven to themselves that there is indeed “something better out there” for them. And they want out. The affair is the self-proof they need to take that final step. So of course, they feel no remorse for cheating. It was just a means to an end.