Hi Harold,
It sounds like Ann is just a bit nervous. Also, keep in mind that Ann may really want to do this and seeing you with another person is just one of those nasty roadblocks she may have to overcome. Someone also mentioned that swinging may not be her forte and that's OK. Sometimes it's better left as a fantasy type of idea.
In our case, my husband was the one that got the talks going and it took me several months to even want to think about him with another person. For us, it took a LOT of talking. You can't even imagine how much talking it took. Of course, my first thought, when he brought up the idea of swinging, was that he was looking for a replacement. I'm not sure if Ann is having this same idea, but just thought. Like I said, it took a lot of talking to my husband about exactly what he was wanting. Of course, I was the one that did a lot of research. I found this board and read just about everything I could get my eyes on. You might have Ann read the threads in here and there is even a search button up above and she can search for the topics of her choice.
As it turns out for us, we've never had a MFM or FMF, but one of these days, we will. For now, we enjoy the couples we play with and when we played with our very first couple, it was so weird that there was absolutely NO jealousy among anyone. It's been that way ever since. Since the very first time, I've always known that he's always going to come home with me. Maybe Ann needs some reassurance that no matter what, you're going home with her. Good Luck!