I think it's great she is there with you.

now about her not knowing you are privy to the real story about her and the Denver dunce. I'd end that secret real soon. I'm my opinion, thats a whopper of a lie she is telling you. you could difuse it like: "I know the real story about you and dunce and while it kills me, I am willing to forgive and work on out marriage". she won't be a happy camper about this, infact, she'll be pissed beyond belief. but it will end the game of "he's just a pal".
it might even alter or cancel any plans they might have of him coming to Chi town, might even slow or end the phone calls.

Boundries.

have a great week!!!