Akira,
In my perspective, you could say that I've been bi-curious for many many years, and while dating women all my life, I've not actually engaged the idea of dating / having intimate relations with a man... until I started my outward transition.
You could say that I was afraid to go to gay bars, nervous about playing with my sexual orientation, etc. However, as I've been out now, and with SO very much support from other T-Girls in my area, I've been able to just let my fears fall to the wayside. As I get out more and more to TG/TS friendly areas and clubs, I have been hit on by men, flirted with, and so on, and have even begun to see some of my male friends in a different light.. all because I've basically been able to come to grips with the fact that I have either always been 'Bi' or 'fluid', whatever have you.
Heck, the other night I was out at a casual STRAIGHT bar, essentially in classy pressed male drab, and I had a cute younger guy come up and start coming on to me... with my GF right there!! I smiled and thanked him for the compliments, and moved on.. but thinking back, I was floored with the realization that I was just hit on by a guy, and I wasn't dressed, and I didn't shy away from it at all! A few years ago, before I admitted to my TG nature, I probably would have run screaming... I must be radiating a more femme presence now or something.
Hope that helps!