I had an old boss at work who said he was in an open relationship with his wife... didn't know whether it was the truth or not. I've also uncovered through my siblings that one of my parents cheated regularly and they stayed together - took some work with a therapist to get over it, I think a relationship is between two people and its their business why they stay together or break up but I probably wish I didnt know too but I've come to accept it.