Adulterers are villains who cheat on their significant others, be they wives/girlfriends or husbands/boyfriends. Sexual encounters are not necessary, as simply seeing two people at once counts (unless it's stated they're in an open relationship or follow non-monogamous lifestyles).

Also, do not add characters who are polyamorous, having multiple lovers is not adultery unless one does so without the knowledge of the other (this remains true even in societies where polyamorous relations are frowned upon).

Not to be confused with Cheaters.