The bold social experiment exploring whether relationships can thrive without monogamy returns. Married couple Chloe and Paul from Liverpool are childhood sweethearts who've never had sex with anyone except each other. Now they want to see if an open relationship can allow Chloe to explore whether she might also be attracted to women. Mark and Tanith from Yorkshire want to find out if having sex with other people can help build trust, which has been under threat due to Mark's past cheating