Not me, but a friend of mine. Her DH's job was in hospitality, so a lot of evening/weekend work, and staying back after work was not uncommon, whether because it was a busy night and needed longer to clear up, or because the staff were having drinks together etc. He was going through a health crisis that required surgery and was potentially going to leave him with a life limiting disability.
He had to stay in hospital post surgery and one day when visiting she got there earlier than she had expected. There was a young girl visiting who he said was a friend, who quickly made excuses then left. We were all thirties, this girl was young (adult, but late teens or twenties), my friend clocked something wasn't right - why would someone be close enough to her DH to visit him in hospital, yet be someone she didn't know about?
She waited until he was discharged before confronting him, but did some digging while he was stuck in hospital and it turned out he'd been having an affair with one of the students who worked PT at his work. It wasn't hard to find out about it because the affair happened during working hours, so most people there knew him and the girl were an item without realising he was already married! She actually spoke to the girl, who had naively bought the 'loveless marriage' crap he had spun her and had probably been just as shocked as she was about seeing the other at his hospital bed.
She kicked him out and he had to deal with his recovery at his parents. Friend is happily remarried, he's never changed and just seems to be in a constant mid life crisis of chasing younger women, and trying to use his status (manager of a nightclub, offers of free drinks etc) to impress them.