Any insecurities she had about herself, your relationship, or her life in general just had a magnifying glass put on them by telling her; by no means should you have not told her, but be prepared for peaks and valleys of being ok or not ok with poly. I think her actions with the time spent together (your self described NRE with your wife) are her attempt to show you she can be what she thinks you want her to be, she may be trying to show you she can be what you are looking for. I say this because at first I saw poly as just a way for TP to sleep with other people (it wasn't but that's how my emotional side viewed it) and I imagine your wife might have the same feelings and is trig to compensate for shortcomings she thinks you believe she has. Reassurance is key, and honesty about what you really want (physical vs. Emotional for poly.)
This, especially. She may very well be trying to show you that you don't need anyone else. If this is the case, it will be very important to clarify that the enthusiasm you had for having your wife back should not be confused with admitting you were wrong and you don't want anyone but her.