A passive/aggressive means whereby a man can extricate himself from an intimate relationship with a woman without being the "bad guy". Essentially, the man insists that he and his girlfriend (GF) engage in a menage a trois with the GF's cute friend. Invariably, the GF will become outraged and tell the man to take a hike. Occasionally, however, the GF will assent, and the man will get to enjoy a hot threesome; in which case, he'd be a total moron to dump his GF.

No matter what happens, this method has a positive outcome.
I wanted to dump Gina in the worst way, but she was such a good cook and so nice that the only way I could bear to do it was by springing the threesome ultimatum.
by succulentboi August 17, 2004
Get the threesome ultimatum mug.