I am not a fan of exposure (not saying not to confront the WAS, but telling 3rd parties has NEVER resulted in a reconciliation that I know of). Please read "facingdivorce"'s thread and how it backfired on him big time.
What is your LONG term goal? If it's reconciliation, then how does telling 3rd parties make that more likely? If you "injure" him socially, or professionally to "teach him a lesson", you will unite them, not divide them. And you'd be very surprised to learn how few outsiders will appreciate you sharing your pain with them. A lot of people resent being dragged into it and many of them see the LBSer as a whiner, nagger, somehow in the wrong. And that makes it all worse. WHEREAS when the truth comes out some other way and the LBSer has clean hands, it just makes them look more dignified. Like they're putting their children's needs ahead of their pain AND keeping a private matter, private. Once your h goes public with OW then that changes things. But for now...
If you take the high road then when the truth comes out you come out smelling like a rose. And the truth will come out, but don't let it come from you. It looks vindictive and nasty and confirms the reasons the WAS used to justify leaving in the first place. It's much worse for your kids to hear it from you when you come from a place of victimization.
As my DB coach said, "it's NOT OUR JOB to "teach them a lesson" or "show them the consequences of their behavior", b/c Life does that for them....
I am not saying you should cover or lie for the cheater, but there's a fine line between outing to punish, and simply being truthful. Look within your heart and see where your motives are coming from. A place of light and truth, or dark anger and pain...
Good luck
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