I'm probably being an interfering old busybody who should mind her own business. However, I have recently found out that a married colleague of my DP (whom I have met socially, and thought he was a sleazebag) has been having a full on affair (for well over a year) with a married woman who works for a different company in the same industry. I've known about these rumours for ages, but a few days ago my DP saw them out together, all over each other like a bad rash, kissing etc in public for all to see. It's made me really annoyed on his wife's behalf.
He is married with 4 children under 10. I don't know his wife very well, but on having a snoop, I see that her fb is full of family photos, recent ones. She clearly doesn't have a clue and thinks they are a happy family.
I don't know the woman he is seeing, well I know her name and who she works for, but not personally.
The logical part of me tells me that this is none of my business, but another part of me wants to send his wife an anonymous message to tell her what's going on. I know that's probably being massively unreasonable, but he is such a slime and I would hope someone would tell me in such a situation so I wasn't living a total lie.
I'm pretty sure I won't do anything with his information, but want to know the general consensus on this sort of thing?