JMHO = just my humble opinion
You think that I should contact OW's H and expose the A.
Yes.
Even though I think that it is over?
Yes.
You may be wrong. I cannot count - certainly can't remember - the number of times a BS wrote here that they were pretty sure the affair was over, and later found out they had been hoodwinked. WSs in the act are
very desperate and devious to keep their fix.
Further, your H has not sent a NC letter. Maybe because you haven't brought it up.
And if I am right and it is over H will be very angry and possibly leave.
Why do you say this?
If he gets very angry, it's because he hasn't decided that the affair was the stupidest thing he's ever done. If he hasn't decided that, he's no better off than if the affair was still in progress. To truly commit to the marriage and rebuild, he has to hurdle this obstacle - eat some humble pie.
EVEN IF, he gets angry, he won't necessarily leave.
EVEN IF he leaves, this doesn't mean he leaves for good.
Finally, think of the other husband. How would you like it if the roles were reversed? You knew something wasn't exactly right in your marriage but you couldn't put your finger on it. Somebody knows your spouse is in an affair but makes a conscious decision NOT to let you know. What would be your first thought when you finally found out the truth?
cfc - no one knows exactly what will happen when you tell the other husband. None of us knows how much he already knows. Nothing to everything. He may be guilty of not telling YOU! No one knows if he or his wife will attempt to contact your H. But, if the affair is still in progress, this will certainly happen - and your H will be madder than a wet cat. But the cat will be outta the bag.
So I suggest you ask your H to write a NC letter that you will deliver. When he declines, this won't necessarily mean anything other than he has not fully committed to the marriage - which you already know. BUT - if he agrees, that's the signal that the affair very likely is over and provides the opportunity to also alert OW's H because you will deliver the letter.
Bottom line - if the affair is really over and he really wants to rebuild the marriage, he should jump at the chance to demonstrate he wants nothing whatsoever to do with the former OW.
JMHO
WAT