Noun
household for three; an arrangement where a married couple and a lover of one of them live together while sharing sexual relations
Source: WordNetmenage-a-trois
I want to see the two CEOs of RIM and [Apple CEO Steve] Jobs working together. The thought of this ménage à trois is absolutely hilarious. Jean-Louis Gassée
Police sources said the menage a trois came to an awkward end when one of the guys started filming the tryst, prompting the woman to become upset. Source: Internet
The proposal was exactly what I had suspected: a Stunners International menage a trois. Source: Internet