I said: ‘We can be better. I can be better. Things do get better sooner or later, for most people.’

She shook her head.

‘That’s you, it’s not me.’

‘What does that mean?’

‘Nothing.’

‘Come on, what does it mean?’

She looked at me for a moment, then dropped her eyes to the floor.

‘How long have you been teaching, Joe? Twelve, Thirteen years?’

‘Thirteen years including my PGCE year.’

‘Three different schools?’

‘Yes. You know that.’

‘And you’re still only deputy head of department. Of a department of four teachers.’

‘So?’ My neck felt hot.

‘So I know teachers our age who are assistant heads. Kate’s a deputy head. Some are even heads already. People who’ve really gone for it, put themselves forward and made the most of their opportunities.’

Trying to keep the anger out of my voice, I said: ‘And you think I haven’t done that?’

She shrugged.

‘I don’t know.’

‘It sounds like you do.’

In a small voice she said: ‘Do you think you have, Joe? Honestly? Or have you just been treading water for most of your career? Just let yourself get carried by the current, nice and steady, until you’ve got into a bit of a rut?’

I could feel my cheeks flushing, heat rushing to my face.

‘A rut?’

‘Ever since you stopped playing hockey. Since your injury. You just seemed to give up trying, and settle for being . . .’

‘What?’

She looked away from me.

‘Settle for being what?’ I said again.

‘Average.’

I rounded on her, speaking through gritted teeth.

‘Don’t you put this on me. Don’t you dare. This was your decision, and no one else’s. It was your decision to go to bed with another man, your decision to break our marriage vows. Don’t you dare say it’s my fault.’

I hated her saying that. Mainly because I’d caught myself thinking it too in the last few years, but thought I was the only one who could see it. And I was the only one who was qualified to have an opinion on it.

She looked as if she was starting to regret going down this route.

‘I’m sorry, Joe, I didn’t mean that, I didn’t mean to say that. It’s my fault. I’m just lashing out in every direction because I know what I did was . . . inexcusable.’

I rubbed my temple with shaking fingers, waiting for the anger to subside. This wasn’t getting us anywhere. What was done was done. I sat down on the windowsill.

‘You should have at least told me,’ I said after a minute. ‘Talked to me about how you felt. Rather than looking for answers in someone else’s bed.’

‘I know. I’m sorry, I’m so, so sorry. The truth is . . .’

‘What? What’s the truth?’

She covered her face with her hands, as if she was finally, fully ashamed of what she was about to say.

‘The truth is, ever since William was little I’ve felt so useless with him, like I don’t know what I’m supposed to do half the time. Don’t know what’s expected of me or what a good mother does. More and more it’s like you don’t even really need me, you two boys, you’ve got this bond that I can’t even get close to.’