Throuple might be the current term for three-way romance but it is by no means a new phenomenon. Neither is the idea of a couple saucing up their marriage by bringing in a third party, though that too is given its contemporary moniker – the titular “unicorn” in Mike Bartlett’s play about the travails of one throuple.
It consists of a midlife, middle-class couple, Polly and Nick, whose sex life has lost its fizz. Kate, a gobby young cockney who is a generation apart, might just be the unicorn to bring it back.
