A bisexual character is shown to be overly sexualized or cheating on their partner. While not necessarily a sign of promiscuity, portraying bisexual characters as unfaithful to their established partners further enforces the idea that bisexual people lack restraint or have no moral compass, and therefore characters who are shown to cheat on their partners are included in this trope.
Characters embracing their sexuality are rarely portrayed in a positive light and this trope perpetuates the notion that bisexuals can’t be monogamous or struggle with a sex addiction. Bisexual characters shown to have a willingness to sleep with everyone they can is often a way to have the audience view them as having no qualms or boundaries and engaging in negative “unhealthy” behavior. When the partner of a bisexual female character approves of or participates in their sexual activity with others, this is often played solely for the male character’s reactions to the female/female titillation. Additional reading: Anything that Moves, A Threesome is Hot.