If this is true she probably feels she is entitled to talk to him whenever she wants and it's none of your business.
Clearly though you don't see it that way. You are threatened by OM (otherwise you wouldn't call him OM). Now did she promise no further contact with OM? Or is just denying it being an EA/PA.
If she promised no further contact and is breaking that you need to establish a clear boundary. She clearly thinks she can continue to disrespect you. As long as OM is still in the picture any and all attempts at reconciation are just a charade.
She can't pour herself in the marriage as long as she still has an out by going with OM.
Now a lot of folks think it's great that she is showing signs of wanting to work on the M. Like she may be ready to begin piecing.
Look I don't think you can piece as long as she keeps turning to OM. Piecing IMHO is about working TOGETHER for the M. She won't give her best as long as she can turn to OM.
So what can you do, she sure seems to want it both ways.
I can see you are conflicted and in pain. I think you and your W have a lot to clear up. I think she needs to once and for all tell you what the heck this guy is to her. I say this because clearly for either good or bad she wants this guy in her life. He could just be a friend, or not. Nonetheless it is not fair to you to live the rest of your life guessing. She needs to once and for all tell you what he is to her.
Once she does this she needs to be open enough so that you dont doubt this. All this hiding needs to stop. The burden of proof is on her.
How would she feel if you snuck around phone calls to a woman. Then when confronted kept hiding them. If it's so innocent why can't she at least be open about it.
I think there is a very clear distinction between this case and others on this board. In most cases the spouse walks away to be with OP. The LBS wants her back. If he/she returns hopefully it is without the OP. Most WAS don't return with OP.
In your cases she doesn't want to leave, yet doesn't want to let go of OM she has to pick one. I know many here would love to have their spouse back, but would you accept OP too if she came back?
Besides a lot of WAW's will pretend to try to piece while they fix their affairs and finally get to leave with the OM.
Maybe GB is just bitter but something smells rotten here.