discordant couple n. a pair of long-term sexual partners, such as a married couple, in which one is infected with a sexually transmitted disease and the other is not. (source: Double-Tongued Dictionary)
Further reading
Brian from Lafayette, Indiana, wonders why chicken is abbreviated CHX in the restaurant industry. Using X as a substitute or shortener has a long history. Medieval scribes sometimes drew a line through the final stroke of an abbreviated word. This...
Martha from Tallahassee, Florida, remembers hearing older relatives announce they were going for their constitutional, a term that traces back to Latin constitutio, meaning “character,” “disposition,” “nature,” or “the essence of a thing.” Its...