‘What happens if one of you doesn’t any more?’

‘Doesn’t what, matey?’

‘Love the other one.’

I wondered what he’d seen, or overheard, or picked up from the adults around him. He was a smart boy and picked up lots of things, without necessarily letting on at the time. Often he’d ask about things right out of the blue, days or weeks after he’d first heard them.

‘Well,’ I said slowly, a painful lump in my throat, ‘then they both have to be really nice and kind to the other one, and remember how they got married because they were in love, and try really, really hard until they love each other again.’

‘So are you going to be nice and kind to Mummy?’

A new thought struck me. In all of this mess that had been created, I’d thought Beth and me were the biggest victims, with the most to lose. But that wasn’t true: William would be the biggest victim, if things weren’t put right. He was not even five years old and stood to lose more than all of us.

‘Yes, Wills. I’m going to try as hard as I can to be nice and kind.’

He picked another of the cars scattered around under the kitchen table and rolled it absently back and forth, back and forth.

‘Can I have Golden Nuggets for breakfast?’ he asked.

If Mel realised that I’d discovered the secret mobile phone in her handbag, she gave no sign of it. She got ready for work as usual, kissed me and asked me twice if I was all right or whether she should take a lieu day and stay home with me.

‘I’m worried about you, Joe.’

‘It’s fine. I’ll be all right. You go, I can do the school drop-off.’

‘Are you sure?’

‘Sure.’

I took our son to school, stood with him as he lined up with his class and watched him trot happily into his classroom. His teacher, Mrs Ashmore, gave me a smile. I smiled back.

Then I drove home and hacked my wife’s email account.

Gmail would give me three chances at the password before it locked me out. But I had a suspicion that all of Mel’s passwords were the same, or variations on a theme. The PIN to unlock her mobile was William’s birthday. Maybe he was the key to her password here as well. Not long ago she had told me her Apple password when William had wanted to download an app onto her iPad – another iteration of Angry Birds. Like me, Mel had lots of passwords for lots and lots of sites, and I suspected that – like me – many of them were the same to make them easier to remember.

I typed in WilliamLuke3.

Red text appeared below the box: Error – wrong username or password.