At his suggestion, we meet at the park in Fulham halfway between our houses. He’s already there by the time I arrive, standing by the gate waiting for me. It’s a miserable fucking day, gloomy and overcast: the kind of dreary August weather I remember from my childhood, before climate change was a twinkle in anyone’s eye. Felix is wrapped up in a thick jacket, his shoulders hunched against the damp chill coming off the river. It makes him look like the brooding hero of a Brontë novel.

We fall into step and walk along the Embankment in silence for a few minutes. The tide is out, and there’s a dank, rotten smell in the air. Felix’s hands are thrust deep into the pockets of his jacket. I wish I’d thought to wear something warmer myself.

‘It’s not what it looks like,’ Felix says finally.

‘And what’s that?’

‘I didn’t hit my wife.’

‘That’s not what she’s told my wife.’

Felix stops and turns towards the river, gazing down at a tugboat churning slowly upriver through the brown water. ‘I don’t expect you to believe me.’

‘I don’t know what to believe,’ I tell Felix frankly. ‘Stacey turned up at my house this morning with a black eye. Why would she tell my wife you’re hitting her if you’re not?’

A muscle works at the side of his jaw, but he says nothing.

‘You need to tell me what’s really going on,’ I urge. ‘Millie’s on the warpath, and trust me, mate, once she gets her teeth into something, she doesn’t let go. If your wife’s playing some kind of sick game with her, I need to know.’

‘She should get as far away from Stacey as possible,’ Felix says baldly.

I shiver. The damp from the river must be getting to me.

‘What does that mean?’ I ask.

‘Stacey’s like a Venus flytrap,’ he says, his tone bitter. ‘She likes fucking with people. She lures you in, and by the time you realise what’s happening, it’s too late.’

‘How did she get that black eye, Felix?’ I ask quietly.

He hunches his shoulders deeper into his jacket.

‘It’s what she wants,’ he says abruptly. ‘She likes me to choke her when we … when we have sex. Until she almost passes out. She likes it rough. I mean really rough, Tom.’ His voice thickens with shame. ‘She creates these … these fantasies for us to act out. I have to attack her. Pretend to rape her. She makes me hit her.’ He looks away again. ‘It makes me sick to my stomach.’

I have no idea what to say, so I say nothing.

He turns from the river, and the two of us resume walking along the Embankment. He doesn’t speak again for quite a while.