Cuckoldry

Cuckold historically referred to a husband with an adulterous wife and is still often used with this meaning. In evolutionary biology, the term cuckold is also applied to males who are unwittingly investing parental effort in offspring that are not genetically their own. Since the 1990s, the term has also been widely used to refer to a sexual fetish in which the fetishist is stimulated by their committed partner choosing to have sex with someone else.