if you tell others - and if she finds out - which is usually the case with someone asking her questions or saying "just thought she should know"
the tendency is for the WAS to revise the marriage even more, in order to defend themselves.
That can make you look bad and you won't even know half the time. If you do know, then it escalates. Character assassination gets ugly fast. Something to consider. Plus you have a son to consider. At my d20's school when she was just 10, her bff's mom kind of went nuts. She had an affair somewhat openly, started using drugs and got arrested, etc.
Some kid made fun of D's bff, and they slurred the mom to the girl. Though the mom was literally sick, maybe she deserved it.
But her daughter didn't.
I'm almost sick just remembering it.
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