PT, I misread your question. I think. I thought you asked about the LBSer exposing their spouse's affair to THEIR families....but You asked about exposing to OM/s family, as opposed to the WAS's? Is that correct?
I would have to think about that. (But I would not ever involve the OM's kids)...but I probably would tell their spouses, e.g., if MY h was seeing OW, and OW was a married woman, at the very least I'd confront HER and let her tell her h say within 24 hours to spare her h the humiliation of having a stranger tell him. But if she refused, I'd probably tell OW's h myself. There are exceptions but yes, that's my take on THAT.
As for exposing my h's A, to MY/OUR family while trying to stay M to my h if he had the A, that is the hypothetical I thought you were asking. That's where I'd keep it private. Does that make more sense? Sorry for the misunderstanding and definitely sorry if this hits a chord...yikes...
j-
M: 57 H: 60 M: 35 yrs S30,D28,D19 H off to Alaska 2006 Recon 7/07- 8/08 *2016* X = "ALASKA 2.0" GROUND HOG DAY I File D 10/16 OW DIV 2/26/2018 X marries OW 5/2016