While I can't speak to anyone else's feelings or experiences, I don't believe crossdressers are inherently bisexual. I think most are either gay or straight, with crossdressing being a totally separate issue. However, I do believe it can happen that crossdressing can cause one to wonder what it might be like to, for example, be with a man as a woman, even though natural attraction is to women. Gender and sexual norms are so deeply embedded and heavily reinforced throughout society that when you're seeing yourself as a woman, it's almost inevitable for the mind to at least consider the idea of carrying out the role we've been conditioned to believe normal for women, despite the fact that nothing about sexual attraction is truly uniform to any demographic. For myself, having seen myself as female from the time I understood the difference between boys and girls, and having had a SO who accepts and supports me since age 13, I never experienced that kind of wonder or curiosity myself, but I've known others who have. Some have followed through with it, and invariably they report that it was not only nothing like they'd pictured, but also that it wasn't even particularly enjoyable because once in the situation they felt detached, just going through the motions, in large part because they weren't truly interested but just acting out what they thought they should want on some level. The one exception I can recall was a friend of mine who rather than being with a man, told her wife about the idea. The wife suggested that they explore the concept but with her playing the role of the man both in mannerisms and sexually, using prostheses. They both actually found it to be quite fulfilling, as my friend was emotionally invested, and her wife got to explore and express aspects of herself that she had suppressed because they weren't "ladylike". However, after hearing how the concept had been so great for them, my wife and I tried the same and got nothing out of it, so once again each situation tends to be unique to the persons involved.