She was trying to hide it, but I could tell she was bothered that they had argued. She made it a point never to raise her voice to her boys, never to shout, never to be sarcastic and never, ever, to raise a hand to them. Not even when Jake, aged seven, had been playing with matches and come perilously close to burning their house down. A poem that hung on Jennifer’s kitchen wall at home exhorted parents to reject every negative emotion in favour of raising their children with only praise, encouragement, approval and acceptance.

The boys were her project, her mission in life. Born only eleven months apart, Jake and Ethan had become all-consuming in the way that small children could be, and Jennifer had quit her job and never gone back. She’d thrown herself into the role of full-time mum with a gusto verging on mania, and was both hugely proud and fiercely protective of her boys. Even when Ethan had joined his older brother at primary school, she had resisted a return to her physiotherapy career and had got a part-time admin job in the school office instead.

Sean walked in, a towel around his waist, hair wet from the pool. It was the first time I’d seen him since discovering the messages on his phone, and I felt my face flush instantly with a burning sense of anger and heartache. And a million questions. The discovery was so raw, and there had been so little time to process what I was feeling – I needed to arrange my expression, my emotions, in a way that didn’t instantly give away the toxic secret I now carried inside me.

I couldn’t bear to look at my husband, but I couldn’t look away either.

He greeted Jennifer with a peck on the cheek – curiously chaste in the circumstances? Perhaps not? – and returned to his suitcase to continue unpacking.

‘There’s a games room downstairs,’ I said, hearing the weirdly forced tone of my own words. ‘A pool table, table football and all sorts. I’m sure the children will find something to do.’

Jennifer nodded, not seeming to notice the tension in my voice.

‘I’m really hoping they’ll spend lots of time outside,’ she said. ‘The air is so much cleaner here than in London. And they spend so much time playing on that damn Xbox.’

Jennifer’s husband, Alistair, appeared at her side in full summer holiday mode: belly-hugging vest top and Speedos, hairy shoulders and bare thighs. I’d always thought they were a bit of a mismatch – physically at least – and they’d turned into one of those couples that didn’t seem to have aged at the same rate. She still had the tall, long-limbed Californian grace that had beguiled a succession of university boyfriends all those years ago, while Alistair seemed chunkier and more dishevelled than ever with his full, scraggly beard and tortoiseshell glasses.