Earlier quoted context omitted.
I don’t know. What if the partner is a bad, manipulative actor, but it is just too difficult to dissolve the marriage? For the sake of children, financial commitments, costs, unfair legacy laws and so on? It’s certainly not unheard of, so I’ll keep sweeping personality assessments based on cheating at bay. There’s clearly also other reasons, I’m not saying cheating partners are always poor martyrs of circumstance.
Technically everything can be used to establish a (operational) perception of a person — and everything can be wrong. Someone wears a Rolex? Maybe they are rich and want to show off, maybe they inherited it from a dying family member. If they however additionally drive a super car, wear designer clothes the likelyhood of alternative explainations goes down. If someone is a nice, cordial and all around good person and…
Cheating on someone is just such a noisy signal. You don’t know why, or what’s wrong with the relationship. You mostly don’t know who is cheating, at best you have a biased sample. You don’t know what they are like to their parents or children, or frankly even their partners - are they loyal to them in other ways, caring for them when they need it?
Relationships are super complicated and judging them from outside takes a psychology degree and extra training. I’m not going to jump to conclusions from a Boolean variable.