I was hoping to interact with you by asking you a question.
I ask this because I was asked the same question, and I had a tough time really digging down coming up with an honest answer.
You want an open relationship with your twin soul. Your wife has expressed she wants to be mono. This path here greatly follows the same path I believe in. The tough question is this:
If your wife, changes her mind and says she wants to connect emotionally and physically with another man, would you be okay with it?
I personally could not accept my wife with another man. I am a complete and utter hypocrite, and its painful. My wife approached me with the idea of opening up our marriage to another straight female, which I think would be great. Like your wife, my wife wants to stay monogamous with me as the hinge in the FMF Vee. The difficult part is this (which I truly believe): Others have referenced poly lifestyle as Pandora's box, that once you accept and open it up, you cannot literally contain and close it back to meet your (meaning you personally, not necessarily now your wifes) views.
This is where I struggle, and I hope to gain some insight from your answer. If your like me, and cannot accept your wife in a poly lifestyle, would you then risk opening Pandora's box???