‘Wow,’ I said. ‘That was brave of him. And did everyone react well to that?’

‘Yes, of course,’ she said. ‘He says he might even be pansexual.’

‘Jesus!’ I said.

‘Don’t swear.’

‘What the hell is pansexual? Someone who’s into nature?’

‘Yup,’ she said breezily. ‘You know: snowmen and stuff.’

Everything was different in the house; there had been a fundamental shift between Karl and me. It was now a place of tolerance and kindness. This new way that we were living seemed to be working for everyone. I’d relaxed. I was getting on well with the kids. I was writing away like mad – I had the beginning and the end of a great story and had pitched it to my agent, who thought she could sell it. I was feeling generally inspired. Karl had been up in Edinburgh for a few weeks (I didn’t ask any questions at all) and when he came home he seemed happy and loving and kind. One night we had actually even spontaneously made love ourselves. And it was so much better without the duty attached to it. Even my father noticed that I seemed happier. Has something happened? he’d asked, with a peck on my cheek. You’re shining, my darling!

Karl had been adamant that we should tell no one about our new arrangement. I felt the same. Except I did tell Ness, obviously – but I swore her to secrecy. It was a Saturday and we were in her kitchen about to have tea. She was trying to fix the Ikea cuckoo clock; it lay in parts on the table. Once the kids left the room I made her catch me up on her latest romance saga – she’d been on a few dates, with women and men. She was pouring the tea, one hand on the lid of the Cornishware blue-and-white striped teapot.

‘Ness,’ I said, ‘Karl and I have come to a decision . . .’ (She, of all people, knew how strong but numb our marriage was.) ‘We’re going to take lovers.’ She paused mid-pour, looked at me and frowned. It wasn’t the reaction I was expecting. Not shock or delight, but disapproval. I always forgot how essentially prudish she was. Or did she think I was coming on to her? Was I coming on to her? What did the agreement mean for her and me?