Doing everything wrong...

[roist]

There are two schools of thought about this. One is to openly expose the affair as much as possible but in a controlled way. This paints the picture as it is and W has to assume her actions. Sometimes this can cause them to reflect and realise they have made a mistake.

In your case as D is already filed by her, I doubt it will push her to want to come back. It could come across as vengeful or spiteful attacking the affair R could strengthen it.

The second school of thought is as Cadet mentioned,you tell the least number of people possible. In saying that I would not cover it up either.Thus avoids a lot of possible negative effects. But most importantly it can make reconciliation easier later on, for many reasons.

But as TX says, do not let yourself be plan B or a doormat. You do not want any R with someone in another R. Final.

Best wishes