I was aware of wanting a man even before I consciously admitted to myself that I'm transsexual. In fact, it was desire for sex with men that woke me up to the fact I need to have a vagina and be a woman, because like Nero I could not see man-on-man sex for myself. I tried but just could not see it happening. This made me ponder I really should have been born with a vagina... oh yeah, that's probably connected with the thoughts I've had all my life I want to be a woman... duh. So I awoke to being trans as a result of wanting men for sex.
After that I still preferred women, and lesbian identification felt very attractive to me. I tried to align with lesbianism. I still have great fondness for lesbians. But once I was on HRT, I began to feel an even more intense sexual desire for men. That will not happen, however, until my SRS is completed. While waiting for SRS I live essentially asexual. But in terms of sexual orientation, I am clearly bi. I would still rather identify as lesbian, as a conscious choice... because to me women loving women seems like the ultimate good in life. But the fact is, I'm bi.
I think Nicole is right about people being potentially bisexual. So what is it that actualizes that potential? I think HRT. Before I started HRT, I desired men but could not see it happening. After HRT, when estrogen had worked its womanly mysteries on my body and mind, when men began to express sexual desire for me, I could see it happening. Now I like to be physically close to men although sex will have to wait until SRS. Now I feel sexual desire, not in my useless joke of a male appendage, but inside me... where my vagina will be, hopefully someday soon.
I would love to have a boyfriend someday. Part of my attraction to men is raw animal lust... but part of it is sociological, my chance to be seen as just a normal woman. This troubles me, because it would mean forsaking my lesbian sisters who I love so much.
My head tells me, Women are better, stick with them and the hell with men. My body urges me to get a man. As you can see, I'm still working through all this. Anyway, I'm not having sex with anyone now.