What Cat was doing is known as "unicorn hunting". Ruby embraces this increased openness, but says that "the reality is that there are lots of people getting involved in these conversations who might not have much education" around sexuality, gender and feminism – which isn’t surprising, considering the state of sex-ed in schools. As non-monogamous dating and polyamory have become more popular in recent years, sex educator Ruby Rare tells me that having a threesome with another woman has become something of a gateway drug for heterosexual couples – with most conducting their search for "a third" on dating apps.