I’m trying to train the desire out of myself, like a boot camp recruit. But it’s not working. Every week that goes by, my feelings grow. Whenever I train with Kerry, we fall into a rhythm together that feels like a substitute for what I really want to do.

The only thing that stops me acting on it is knowing I couldn’t live with myself if I hurt her again.

I don’t think she notices. She’s as focused as Coach Coley when we’re working out. We talk about VO2 Max and muscle-building diets, and avoid anything about feelings or the past. She also barely mentions Tim, though she says he’s hopeful he’s done better in his medical resits. Which is good.

I mean, I still hate the prick, but I want her to be happy.

Though today I wonder if I’m getting the full picture. After five weeks of training, we’re finally ready for the big event: a mini triathlon in Herefordshire, in the grounds of a stately home. We’re staying over in a pub to save having to drive back tonight. When we check in, I offer to pay for her room at the same time as mine – my parents reinstated my allowance after I took a urine test to prove I’m clean. It makes me feel like a loser every time I take their money out of a cashpoint, but I will find a way to pay them back.

‘You’re all right,’ she insists. ‘Tim’s already paid. As a treat. He . . . well, he thinks I’m here on my own.’

‘Oh. Right. Makes sense, I guess.’

Except, does it? As I get ready to race, I wonder. Kerry lying to him isn’t exactly healthy. And why hasn’t he come to support her? If I were with Kerry, I’d always be waiting for her at the finishing line.

I pull on my wetsuit, glad it hides the ugly bump and scar of my ICD. What do I know about relationships?

We walk to the lake together, along with hundreds of other crazy people. We’ve agreed to do the race aiming for our own personal bests – so she won’t hold back to humour me when she’s swimming, and I won’t hold back during the run.

But as I launch myself into the lake, she’s there at my side.

‘You . . . go . . . on . . .’ I gasp, in between swallowing great gulps of cold water.

But she doesn’t let me drop behind and with her next to me, I’m safe.

We clamber out on the other side. She’s wearing a short wetsuit and her calves are mottled by the cold water, but she couldn’t look more gorgeous. We laugh as we get on our bikes, and keep laughing as our legs burn going uphill.