For example, in the British Bangladeshi community, those who are cohabiting are seven times more likely to be with someone from another background as those who are married.It suggests that cultural barriers still make it more difficult for those in inter-ethnic relationships to formalise their status by marriage."But the other side of me was concerned about what this means in terms of intimacy and how the dynamics would work." When Leah and Ryan met at a wedding four years ago, they didn’t expect to develop this type of arrangement.Neither of them had had an open relationship before, though it was something that Leah had contemplated.
But the figures also shows marked differences in attitudes to outsiders within different communities – often reflected in the whether people are married or cohabiting.
“I like everyone to meet each other and be friends and stuff,” he explains.
"There was a side of me that was ecstatic – the teenage boy in me that wants to fuck everything I see," reveals Ryan, a millennial in an open relationship.
By contrast 85 per cent of people from mixed-race families have themselves set up home with someone from another group.
People from an African background are five and a half times as likely to be in a mixed relationship as white people, while those of Indian ancestry are three times as likely.