<human>: This is a bit of a long one so I apologize in advance for the wall of text.

I work in a community that is pretty small so even though I have had several employers I don't burn bridges and I try to be as friendly as possible. My former boss and I were relatively good friends and there were no hard feelings when I moved on. I met her husband and my wife and I had been to dinner with them before. They are good people.

while I was working for her I noticed her getting close to another guy who is in our line of work. After I left I started hearing rumors that she was fooling around with him. Nothing hard core but certainly not appropriate for a married person if it was true. But the second hand sources just didn't seem right so I let it go. 

Cut to a few weeks ago and I run into another former coworker.  They confirm that the relationship was real, serious, and then had just ended around this past Christmas.  Now I'm torn. I know the husband and he's a good guy. He doesn't deserve this kind of deception. 

I feel like someone should tell him, but then I wonder if maybe they have an open relationship. Maybe he has known longer than I have. Do I risk getting involved and burning a lot of people in the process? Or should I just keep my yap shut?

Provide a brief overview of the text.
<bot>: should I tell someone I kind of know and like that his wife probably cheated on him. Doing so could jeopardize my standing in the business that I work in.