You are not alone my friend... this forum is filled with such stories of relationships starting out this way... hell all poly relationships seem to start out with a great deal of emotion in the form of fear and jealousy.
Everyone has had some really good things to say, I especially want to remind you that your wife loving another can bring worlds of good things for you in your relationship with her. Her happiness can spill over into other areas.
The only thing that hasn't been said that I think is important is to give it time. It is early days yet and a very new feeling and experience for all of you... there is much work to be done in the way of communicating needs, boundaries, expectations, emotions.... when the dust settles, if it is meant to be, I hope you will find the compersion you seek and embrace the new connection and closeness you will have with your wife.
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