Honestly I don't even know what my sexual orientation is, but I suspect I'm either bi or a heterosexual woman. I've thought about being with men, but only as a woman with the correct plumbing downstairs. The thought of someone in my back door just grosses me the hell out.
As for women, I do find them attractive and I've been intimate with my wife for years, but usually I'd have to visualize myself as the woman when having sex. And then, even though in the heat of the moment I could find physical pleasure, afterwards I was always emotionally distraught because I was back to reality, stuck in a hatefully male body. There's nothing like sex to hammer home the role you are playing in intimacy. I'd often have to excuse myself afterwards so that my wife couldn't see me in tears over it.