Expert Q & A Answers About love and swinging

My wife and I are swingers...but lately she seems very interested in one other person. How do I talk to her about?

My wife and I have been involved in the "swinger" scene for some time now. It's been a wonderful way to express our sexuality as a couple over the years. However, I've sensed she has had more than a fleeting attraction to one of the other husbands we've been playing with in the last month. I'm somewhat surprised because we've always been so open with one another, but I don't know how to even bring this up. How can I address this with her without her feeling like I don't trust her? I don't want us to have to change our lifestyle.