Hi, dinged. Thanks for the PM. I don't generally tackle threads that are so far advanced, but have gone back and read your original post. This is a very good topic, and for anyone who hasn't read that post, I would recommend it. I haven't read the other comments, so sorry if I'm repeating.
What you described is definitely a pattern. I don't think anyone can deny it. It is, however, not always the pattern. It is not the pattern of my current relationship, because my partner was poly from the get-go. (That has its own set of challenges.)
Ironically, it was my pattern in my marriage, so I always wonder if I'm getting a nice dose of karma in this relationship. I agree that many of the people who use polyamory to hang on to an old partner and introduce new ones may not be poly at all. With my new partner I would love to be monogamous.
I don't think you can force a person who has this RH syndrome to buckle under and give monogamy another go. It wouldn't have worked for me, because after 28 years, I felt I was done trying. I felt the years were slipping away, and with them, my chances of ever experiencing a healthy loving relationship. I think it was only when I reached this point (and it was pretty messy, I literally could not stop crying for weeks, even on medication), that my husband really took me seriously, looked at himself and said, "You're right. I have never allowed myself to open up to you fully, because..." Unfortunately, it was just too late.
I believe that if he had been strong enough to hang in there with me, allowed me to dance the dance that I so desperately needed, and done some work on himself, we may have made it. Instead, he tried to force me by putting on the financial screws, which was his pattern of control. Or maybe we wouldn't have made it. Maybe I would have gone from partner to partner, with my own ego intact, and never learned the hard lessons that I have by leaving the safety of the marriage and putting my heart and soul into a relationship which is very loving and very healthy, even if he is poly.
I haven't kept up with your situation, but it seems you have let your wife dance her dance and are still feeling resentful and hurt. I don't think things like this can be mended with feelings like those going unresolved. Maybe you need a trial separation? Maybe you both need to look at the specifics of your relationship that aren't working? Are you in counselling, not for polyamory, but for your own relationship?
Even though your wife is doing what she's doing, if you want to give your marriage a chance, you both need to work on that, not just on her being poly (whether she really is or isn't). If she refuses to work on your relationship, I would go for the trial separation.