Bisexuality Support Group
Bisexuality is a sexual orientation which refers to the aesthetic, romantic, and/or sexual attraction of individuals to other individuals of both their own and the opposite gender or sex. Most bisexuals are not equally attracted to men and women, and may even shift between states of finding either sex exclusively attractive over the course of time.
That said, there is a lot of confusion and erasure surrounding bisexuality. Many people will assume if you are in a heteronormative relationship you are then "straight." If you are in a same-sex relationship you are "homosexual." The fact is you can be in either and committed and still be bi. Bisexuality is simply the matter of attraction. Your attraction is more the deciding factor for what label you might choose to use than your actions.