Metamour

Metamour (noun) – Your lover’s lover. In polyamory you may have a romantic relationship with someone who has more than one ongoing romantic relationship. Someone that your romantic partner is in such a relationship with, but you are not, is a Metamour.

Example

Chris is in a romantic relationship with Jenny. Diva is also in a romantic relationship with Chris. Diva and Jenny are just metamours.

Monogamy

A relationship style in which a person shares sex and/or romantic love with one other person. Most commonly, monogamy is practiced by couples that are exclusively sharing sex and romantic love with each other. There are relationships in which one partner practices monogamy, while their partner practices some form of non-monogamy.