I have looked it up and have found "Sexually or romantically attracted to both men and women."
And you have also said you're not single.
Now the problem here is that if a Bisexual is feeling sexual or romantic to any both men and women, What happens to that if you started dating 1? Will you still be sexually or romantically attracted to the other gender? Or is it just gone so that all of your sexual and romantics stick with your lover?