Open is a bold new social experiment, following a grou pof currently monogamous couples as they explore for the first time whether they would be happier in an open relationship.
Though still largely taboo, the question of whether or not humans are truly suited for monogamy is a universal preoccupation which continues to divide opinion, not only among scientists, but among the public at large. But what are the implications of renouncing monogamy?
Assisted by sex therapists and relationship coaches, the couples will embark on a series of intimate challenges to road-test if the idea of having sex with other people is at odds with maintaining a committed relationship.
In this first episode, Welsh sweethearts Mady and Nathan are interested in bringing another woman into their relationship, a process that begins by having a threesome.
But after their first sexual experience with an outsider doesn't go to plan, are they in danger of ruining their entire relationship?
Also keen to open up their relationship are married couple Jon and Danielle from Bolton. They're interested in having group sex, but will they be able to overcome the demons of their past?
Open: The Great Sex Experiment begins Friday 01st April at 10pm on Channel 4.