Being married is about legal rights and shared financial goals and responsibilities, yes, but really it is about the other stuff. The nebulous, nuanced stuff like secret in-jokes and pet names – ‘you had to be there’, ‘Oh, it’s just something we say to each other’ – having a private, non-verbal language whereby a single look might say ‘let’s get out of here’ or ‘he’s a wanker’ or ‘I love you’. Different looks, obviously.

