It sounds like all the right discussions have been had, and that you have a great support network for all this, that's awesome. My wife went through a lot of the same emotions you are when I brought up being Poly... I think it's pretty standard. Jealousy, feelings of inadequacy, etc. I had some of these feelings myself when she took a lover.
What helped her get over her worked up jealousy was taking a lover. That kindof puts into perspective what has been said - I guess it actually hits home when you experience it. We're still new at this, but hey, maybe you need a boyfriend.