Ha, great thread. Brings back some old memories! And it looks as though I had it all a little more together than as of late.
I would say with my experiences in the past three years, that bisexuality is more or less a fluidity for me. Some days I am attracted to women, some days not. But on the off days, I can't say I am raging with male fantasies, either. That is to say, sometimes it's both, sometimes it's one, and sometimes it's neither. But I chalk those last sometimes to just a bad day.
However, as I am the one you're talking about being originally someone who thought my orientation was bi, and then later realized a lot of what I was feeling wasn't JUST orientation, I can see where the water gets a little muddy. I am definitely more confused now than I was then, three years ago, but when it comes to Bisexuality, I can safely say in my case, that it doesn't make the married life all too easy when you have a wife who feels insecure about the fact of my liking boys. She knew before we went on our first date, but I think we both might have wished it to be a phase. So we fell in love and married, and I don't think I ever lost male attraction. It came, it went, but I just put it with my attraction to females... as in I felt it, but that doesn't mean I have to act on it. I am satisfied in being married to someone I love.
Well, I did ignore it for a spell, but throw in the military for the cause of that. And the drama of being injured and discharged for it, transitioning from an active, working, contributing member of a relationship to the "house-wife", if you will, and my recent admission of being a transsexual, and we have a very confused bisexual in a marriage with a wonderful woman, but who is straight and sees no future with a transitioning mtf transperson.
So I guess my case is different than most, but I figure I'd spill my thoughts on the topic just to keep this going. It really is interesting to hear other people's thoughts.