A bit of a firestorm has erupted over on Andrew Sullivan's The Dish blog in regards to who or what constitutes being bisexual, with some readers going as far as to postulate that bisexuals don't even exist. It's a fascinating exchange of input and ideas, and well worth a read if you have the time. I confess to having always been a tad curious (bi-curious?) about the parameters of bisexuality, and readily admit to not having formed a clear notion of it yet.
Firstly, we have to define what it is to be bisexual. Are you attracted to both men and women? If so, in what manner? Physically, or mentally/emotionally, or both? Does a physical/mental attraction constitute actual bisexuality, or does it have to also be physical? What if you find yourself attracted in some way to a person of the same sex, but have never made love with them, nor do you plan to? See, there are a lot of questions that arise with this, and they're not always easy to answer.
Without a clear working definition (for the sake of discourse), we're already adrift when it comes to understanding what it is to be bisexual. I, however, have some criteria that seems reasonably sound for the purpose of defining the term. First, you must be both physically and emotionally attracted to people of each sexes. Second, you must have copulated with members of both sexes (preferably more than once). Finally, you must have been in a relationship with someone of each sex.
The aforementioned criteria was developed because I feel as though nearly everyone, if they're honest, has some sort of attraction, in some way, to people of both sexes. It may not cross over into the "I want to have sex with them" category, but it is there. This is why the second and third criteria are so important. It's like if a person admires architecture. Unless they actually take a T-square in hand and successfully design a building, then they're not an architect.
This is why I often scratch my head at so many admissions of bisexuality. When you scratch the surface, they don't really fit the criteria. And there's the rub: We have a lot of folks out there claiming to be bisexual who, in fact, aren't, and a lot of people who pretend to be heterosexual that are in-fact bisexual. It's a funny old world, innit?