There was only one of the two of you together. It had clearly been taken by Dina, evident from the edge of her bronze forearm in the frame. She’d lifted the phone over her head and snapped the two of you next to each other, your head close to hers and a slightly dazed expression on your face. The two of you were illuminated by the camera flash, in sharp contrast with the dim lighting of what looked like a nightclub scene behind you.

I looked at the date and location on it and felt a slight tremor of unease. It had been taken last summer, in Southampton. And I remembered being in a club like this. With April. And how I’d gone to find her with a couple of drinks and been absolutely positive that you were standing next to her when I caught sight of her.

I was so sure it was you. You, who were supposed to be in Birmingham but were for some reason in the same club we were, talking to April.

You were out of sight by the time I made it over, and when I handed April her drink and said, ‘Was that Niall?’ she gave me a strange look.

‘Niall? No.’ She glanced around, considering. ‘I guess he looked slightly like him. Which makes me feel weird for flirting with him.’ She laughed and took a long sip of her drink. ‘But definitely not your husband. Jesus, can you imagine what he’d say if he saw us here?’

I remember my certainty that I’d recognised you evaporating, chased away by relief that you hadn’t caught me out drinking. And I suppose, after that, the drink did a good job of making me doubt it had ever happened.

But it did happen, Niall. I’ve saved the photo that proved it. You were there, with Dina. And April … lied about it.

It left me feeling like you’ve poisoned everything, that realisation. I couldn’t even trust my best friend, could I? She hid your affair from me, when I thought she’d always been honest. Particularly about Dina and all of her bullshit. Particularly about that.

I felt lost, and furious. And desperate to call you up and yell at you. There was so much I wanted to say, but my pride wouldn’t let me even think of it. I’d told you to get out, and I was going to stand by that if it killed me.

But then the idea of writing to you came to me, and it seemed like the answer. I could pour all of it out on paper, and then decide whether to send it to you, or burn it. So for an hour, that’s what I did. Right up until now.