They may or may not ask, but I am betting that the R will not work out anyhow b/c OM is what broke up the M. If you stop and think about it, later in life your kids may ask or even other people will ask, "How did you meet?". Now of course they can lie, but the truth is "Oh, I/we had an affair" or "Well, I was cheating on my first Husband". This will always be part of their history and everytime the OM will see you he will know the underlying hate you have for him. He is almost 10 years younger than her, right? There are so many things that are going to put adverse pressure on a R with them that it just won't last. I think in your sitch which is further along than mine, all you can do is be friendly and live your life. If that means you meet someone else and become involved then so be it, if not and they fall apart and she wants to try again, you cross that bridge when you come to it.
Formerly "missherlove"
Me49 XW49 M17 T19 S16 D20
Expose yourself to your deepest fear; after that, fear has no power, and the fear of freedom shrinks and vanishes. You are free.