I had a coworker who would tell me "stories" about some of the odd behavior of his wife when in the company of one of their daughters' boyfriends.
She would go on "walks" with him, just the two of them at times.
They both attended the same gym.
He woke up in the middle of the night and found her asleep (pretending?) in the living room next to the boyfriend who was supposedly playing video games.
She would have him pick up groceries for the boyfriend and his friends sometimes when they came over.
This was all unsolicited. He just started telling me all of this, I suspect because he knew what was going on and wanted to confirm his suspicions with an outside opinion without asking outright. When I told him what I thought he said "I don't think my wife would do that."
He knew...
Thing is, I wouldn't personally involve myself in these matters as a third party. Women are going to do whatever it is they want and if you overtly try to stifle them it may embolden them, especially if you're on the outside looking in, they may resent the accusation and become spiteful.
I'd leave it alone.
