Can I throw in a bit of a different perspective?
I probably prefer women, all in all. In that, out of 100 women and 100 men, I'd probably fancy more of the women, and most of my fantasies involve women, in fact, until about the age of 17, I was almost certain I was gay totally, although that might be more down to teenage boys than anyhing else :)
HOWEVER, I have only ever had boyfriends. I have slept with probably about equal amounts, but I only seem to get to the "relationship" bit with men. And I love DH and fancy him much much more than any other person, male or female.
I suppose I am bisexual - I wouldn't rule out having a relationship with a woman, it has just never happened, and I intend to stay married to DH, so I suppose it never will. I suppose you get more choice with the opposite sex or something, so you have more chance to find someone you love, or maybe it is just easier in general, maybe I don't want to rock the boat, who knows.
Having a label for my sexuality just has never really come up - the people that would care just assume I'm totally straight when they see my husband and kids, and before I settled down I moved in circles where I actually knew more gay and bi people than straight. In fact, at one point I counted up, and I knew more transexuals than fully straight people in my close to medium friendship circle. In fact, I remember being really surprised by someone referring to me as "bi" in conversation - I'd not really considered it before. DH is aware of my tastes, but it's not really relevant, beyond a "ooh look at that fit woman on telly" kinda thing.
I see it as about the same as the fact that I tend to fancy pale skinny dark haired men, but have had boyfriends who were muscley, tanned and blonde. Doesn't mean I fancied THEM any less, just that they weren't the usual type I went for.
So...could he have meant that?