getting her outta Denver is a good start, assuming the other Guy is in Denver. My personal belief is to not tolerate any contact with other men. I mean, how can she work on the marriage while living in fantasy land with someone else.
I'm sure you've read other threads on here about the same situation. some let other people stay involved and some don't. I believe that is one boundry that cannot be crossed. the longer you tolerate her contacting the other guy, the more normal it becomes, and then it's easier for other boundries to go by the wayside.
just my opinion. listen to some other opinions and then see what is best for you.
Good luck, I know this sucks, but you'll get through this.
