"can someone tell me what i am feeling and why i am thinking about this???"

My take: you're over thinking it - don't worry about it. You love your fiance? Cool. Women are sensual. I have found myself to have some attraction to a few women although don't consider myself interested. For those open minded to it, sexuality is generally not either/or, but more on a continuum. Ya might 90% attracted to men and 10% to women. If you're in love with someone you want to be with, it doesn't matter anymore than finding you're attracted to a man. Enjoy the feeling if you like, but there's not much stake to put in it unless you are having second thoughts about your man. Or if you're thinking about changing the nature of your relationship or cheating.

If you think about it, just because a person falls in love, would that mean that suddenly they lose the ability to be attracted to another human being for the rest of their lives? Hardly. I can tell you this. Although I spend little time indulging in those thoughts while my dear husband is away, I do more often now because hell it's been 3 months and I'm still a sexual being - very much so. So I enjoy them and don't worry so much, and I save up my lovin' for his return.

So in short, forgeddaboudit. 'sallgood.

Well, perhaps the reason, in your fantasy, you cannot get past fantasizing about kissing a woman, is because you've never gotten past that in reality.
You are obviously attracted to women. You just need to figure out if you are sexually attracted, emotionally attracted, or mentally attracted to these women. There is often a difference. For example, I am physically attracted to women, sexually attracted to men, emotionally attracted to only the person I am with, and mentally attracted to intellectuals.

Maybe you should get with your old friend and see how far things go.

Regardless, I don't think this is anything you should be worried about. It is perfectly natural to be attracted to people that you wouldn't normally find yourself attracted to, regardless of sex.

you have to stop and think who will be hurt in the long run for a few minutes rolling in the hay. is it going to be worth it or is it for selfish reasons. it is normal to feel attraction for people obviously. that preschool teacher is probably happily involved already and not looking for you to break up what she has going. since you are already involved maybe you should work on your sexual relationship with that person and stop wasting your time lusting after someone else's mate.