I smile but she doesn’t. She’s debating whether to tell me that she knows. She knows Charlie and Laura. I mentally place a bet that she won’t tell me. That she’ll play her cards close to her chest.

‘I know. But you know they’ve been here, don’t you?’ We stare at each other, unblinking. ‘They must have told you.’

So that’s what she thinks. She thinks I knew.

‘Is that what he said? That I knew? I had no idea. None whatsoever. Well, I had an idea that he was seeing someone else. But he forced the children not to tell me. He made them.’

I see the shock on her face. She wasn’t expecting this at all.

‘How? I mean, what did he do?’

I shrug. ‘I don’t know. But they never uttered a word. When I asked where they had been, they just kept quiet. When I asked how they got jelly on their “My Daddy is a Scientist” T-shirts, they just stared at the floor.’

‘Maybe they knew it was wrong. Jack’s not like that.’

No. You don’t want to believe he is. Because your son is with him right now.

‘What was wrong? Telling me about your affair? That’s not wrong, Katy. The fact that you were fucking my husband was wrong.’

I remember my episode with Louise and my promise to myself and shut up quickly. Katy’s panic-stricken and I immediately regret being so horrible. She’s close to tears.

‘I didn’t mean—’

‘I’m sorry. I shouldn’t have said that. But you know how it makes you …’ She nods. ‘He made my children scared of their own mother, all because he didn’t want to be found out.’

She wrings her hands and glances at a photo of Jamie. I look at her hands. Red raw. The house is immaculate. My God. He’s doing the same to her as he did to me. A chill runs through me. I reckon she’s just sitting here in her sterilised home waiting for him to turn up for inspection.

‘He told me you knew. That you had an arrangement.’

I can’t help it. I laugh. Really loud.

‘Really? You really believed that? Fucking hell. Anyway. That’s not what I’m here for. I want to help you. And you can help me. I wondered if you’d be interested in making a statement. Saying what Jack is like. I’m trying to get my kids back.’

She pales. Her eyes narrow.

‘What do you mean, get your kids back?’

Oh my God. He never told her. He never told her what he’s done.