Your wife isn't a swinger, thats the problem.
You were hot wifing. She got to have her cake and didn't have to come to grips with her jealousies and insecurities. You came to grips with yours a while ago, you wanted her to play around, and she did. Then suddenly she sees you doing the same and that visceral green monster comes out even though logically there is no reason she should have it.
But thats only part of the problem. The real problem is that you don't communicate, or more she doesn't. If you can't talk about sex and swinging, you can't really be a swinger, communication is the most important swinger "trait".
Finally by giving her the option for other men without you, you have created a grass is greener situation. She has a place she can go when she leaves you if she chooses.
Basically you done goofed. It happens all the time here, and I really makes me sad because we have seen marriages die on this board do to these kind of mistakes. It will be up to your wife to rationalize her behavior and emotions.