Here are some misconceptions about bisexuality I've encountered, even among those who are gay/lesbian:
1. "Bisexuals are confused homosexuals." False. As we are learning with more and more certainty every day, human sexuality is a broad spectrum with many variants that may or may not be gender related. Even within the realm of heterosexuality, we find a slew of different preferences.
2. "Bisexuals can't be faithful to one person." False. As in any romantic relationship, fidelity is key. We all have things we like, but might not necessarily find all of those things in one person. If I am in a relationship with someone of one sex, yes I still find some individuals of other sexes attractive but do not pursue them.
3. "Bisexuals are selfish." False. As previously stated, everyone has different attractions. Being attracted to members of different sexes does not make you a sexual glutton. It makes you ...well... YOU.
4. "Bisexuals only want group sex." This is probably the most common one. Some may like that sort of thing. I don't. I find sex very intimate and personal, and I struggle with the idea of being with more than one person at a time. To each their own.
What other misconceptions to you encounter, and how to you respond?