Maybe the reason that so many of the women you talk to have boyfriends is this: There's something alluring about the self-confidence of a person who isn't looking. You know how they always say that as soon as you get a guy/girl, everyone else starts hitting on you? Well, maybe that's it. These women you are interested in have that special quality about them that comes from not being interested.
It may sound silly, but I'm sure that's got something to do with it. I am absolutely not flirtatious, and I try to flash my ring or mention my fiance whenever talking to a guy I'm not friends with. But it doesn't matter how careful I am!

I've been asked out more since I got engaged than I ever have been in my life. I must just be giving off those happy/in love pheremones!