The whole 'gay, bisexual, straight' thing is way overplayed in common culture, especially Western culture. There's an unspoken assumption even among the gay community that gayness must be True Gayness with no exception, heterosexuality must be True Hetero with no exception, and bisexuals must be sex maniacs who are attracted to everyone.
The truth probably falls more along the lines of something like the
Kinsey Scale where most people
could probably find someone of the opposite or same sex they were attracted to if they allowed themselves to. (See Ancient Greece). It's just that society, especially Christian-influenced society, tends to make it much easier for those who lean toward heterosexuality and
could is a hell of a long way from
will or especially
should.