In ethically non-monogamous (ENM) relationships, a metamour is your partner's partner, someone with whom you share a connection indirectly through your mutual relationship to the same person but with whom you don’t share a romantic or sexual relationship.

For example, if you are dating Alex and Alex is also dating Taylor, Taylor would be your metamour.

The relationship between metamours can vary widely: some may form close friendships, others may maintain cordial but distant interactions, and some may have minimal or no contact at all, depending on the boundaries and preferences of all parties involved.

The concept of a metamour highlights the interconnected and cooperative nature of ENM dynamics, emphasizing respect, communication, and the recognition of shared affection or involvement with a partner.