Hi Spodder and RosyRump, and thank you both for some good advice!
As of right now, I'll be following AussieLover's advice about finding out how F feels before I even approach this with my wife again. I feel it's a lot safer because, not only has F implied she finds me adorable but wouldn't want to hurt my wife or her husband (which I take to mean she does have an interest in me), F tells us both that we're stuck with her and nothing would push her away.
Spodder~ we've known F for about 7 years now. We're on pretty intimate terms, though nothing of a sexual nature as yet. The closest is sometimes she likes to greet us with kisses. I always love that.
Anyways, my attraction for F started as romantic and evolved towards being sexual. I'm not the kind of guy who can just have sex with somebody; I have to love them and I only ever make love. What my ideal has evolved into is having a perfect triangle with my wife and F, all thee of us in love together and integrating our lives as much as possible, with plenty of room for F's husband to be around us. I know my wife and F may not fall in love with each other, so I am prepared to let things evolve as they will, so long as they both and F's husband are all
ok with it. If I discover that this won't work at all, at least at present, I will still be happy with the relationship we all have. What this boils down to right now is finding my peace of mind.
RosyRump~ I very much like your idea of having a sit-down with them both and sharing symbols of my devotion to both my loves. I will keep that in mind should the opportunity present itself.
Thanks again for your input and support! This is the most difficult thing I have ever done, and I appreciate all the advice everyone has given.