Question for the ladies but everyone welcome.

My wife and i had recently discussed a 3sum. It would be us and anohter woman..I am the one who brought it up to her. A long time ago before she met me she had a experience with a girl. Since then she has never been with a girl since...But i am in iraq now and have been for a while so we have been away from each other. She did agree to have a 3sum with me when i get back from iraq. So like when she agreed to it i would start talking to her about a girl with us during phone sex and she would get really turned on by it....and she was telling me things she wants to do to the girl also. Well after all this i have realized that a 3sum is not what i want and def not ready for it. I am so in love with my wife i dont think i want to see here with someone else right now, but maybe thats just cause im in iraq and havnt seen her in so long. So i let her know i wasnt feeling good about her geting so turned on by this....So we talked about it and we agreed we wouldnt do it. Untill we are ready for it, basically whatever i want she pretty much agrees with it. But my wife said its like a switch for her that she can turn on and off as far as being turned on by a woman or not being turned on by a woman. Does anyone understand this? Im basically worried that she really wants a woman now and she wants to try a woman.... My question is has any women ever heard of this "switch" my wife says she has......And also do you guys feel i have anything to worry about based on what ive told you. And im in iraq so my responses on here might be kind of slow. Thanks...I just want the best for my wife and I love her so much, it all just kind of worries me. Oh yeah and she said she would really only enjoy it if it was with me, and she said she wouldnt want to do just a one on one with a woman. Can any ladies give me any help..