Wiktionary
n. (context idiomatic English) A relationship involving three persons (usually two women and one man or two men and one woman) among whom there are conflicting and compete attachments of a romantic or emotional nature.
Wikipedia
Eternal Triangle were a London-based pop group managed by Julia Morley. They were an early act to cover Harry Nilsson songs, releasing their version of "I Guess The Lord Must Be In New York City" on Decca Records in 1969.
The group were based in Chelsea and the members were Sally Kemp, Bill Thacker and Billy Butler.
Usage examples of "eternal triangle".
Then he sat looking out of the window at the eternal triangle of the Boxley housetops and predictable trees filling from suburban spring to suburban summer.
I am referring to the situation which the gentlemen who pass among us in these days for dramatic critics, invariably call the Eternal Triangle.
But let them have it as an example of the eternal triangle, the trinity of hate.
A musician of genius, who could play several instruments, including the eternal triangle, Rannaldini had been persuaded by Cecilia that he would only have the ultimate control he craved if he became a conductor.
Benson's murder was no more than the outcome of the eternal triangle.
It's the old story of the eternal triangle, complicated by the villager's resentment of change&mdash.