Sorry to hear all that. I'm sure that the OM is stringing your wife along. He probably has no intention of giving up either relationship. I'm sure she can sense that she only has part of him...that's what is so attractive. On the other hand, you are still just so easy to get that it is unattractive. How about switching things up a bit...get yourself out there. At least look at other women. You might find over time that your wife isn't all that and a bag of chips. And she'll know when you aren't pining away any more and it may appear more attractive to her.
I'm curious...how is it that your ex-wife is able to have such a relationship talk with you? Why would you even go there? Cut off any talks like that.
You cannot be lonely if you like the person you're alone with. Dr. Wayne Dyer