Since there is not a stereotypical bisexual appearance, way of acting or type of clothing, bisexuals are usually assumed to be either heterosexual or homosexual. Bisexual men or women in a gay and lesbian march are assumed to be homosexual or straight supporters unless they are marching as a bisexual group. A bisexual man and woman in a relationship would appear to others as a straight couple and similarly two bisexual men together appear as a gay couple. Where there is prejudice against bisexuals, it is hard to challenge these assumptions. These are common misconceptions.
Bisexuals are no more or less promiscuous than any other group.
Because most bisexual people have had to think deeply about their sexuality, they also may have had to seriously consider the sorts of relationships that work for them. Contrary to myth, a bisexual does not need to be involved with both a man and a woman, nor does attraction involve acting on every desire. Some act on them, some don't. Many bisexuals have long term monogamous relationships, others may have a greater number and range of partners. Some may cheat on or deceive their partner as occurs in other groups but many are faithful or honest to their partner.