In polyamory this term is used to refer to a romantic and or sexual partner with whom one has a relationship, when the relationship is not considered as important as a primary relationship. See the primary partner node for more information.

Many people actually like being a secondary because they feel it is a much "lighter-weight" relationship. You get a lot of the fun stuff (dates, sex, good conversation, and so forth) without a lot of the burden (providing emotional support to the level that a primary would, driving to the store at two in the morning to buy tampons, and so forth.) Of course, some people think that the 'burden' is actually a lot of the good stuff in disguise and not a burden. (I think it's the good stuff in disguise and a burden.)

Secondary relationships can work well if everyone involved communicates about what is happening and what expectations are.