You know, I think if the person going outside the relationship has exhausted all possibilities and has warned their partners that they will look for physical but not emotional satisfaction from someone else if they don't get it at home, then it makes some sense. I know people close to me who dealt with that. Literally years of having a roommate who often wasn't very nice versus a spouse.

They made clear what they intended and why and were clear about what they'd need to stop that direction. If someone can own that, then not great exactly, but I get it.

The betrayal part I will never understand.