Sexual orientation is about the gender of those who I fall in love with, not (necessarily) about the gender of those who I have genital sex with.
Some men are capable of functioning genitally in configurations which are circumstantial adaptations at odds with their essential orientation i.e. men in prison, and straight survivors acting out.
Wanting to be gay if you're not will no more make you gay than me wanting to be straight would make it so (because I am indeed gay).
Sex is about an act, orientation is a fundamental characteristic.
With that said, I'm also aware that for true bisexuals, the water is a lot muddier, but I have no experience to share in regards to that.