KATHY WAS GETTING CARELESS. It was inevitable, I suppose. Having gotten away with her infidelity for so long, she started getting lazy.

I returned home to find her about to go out.

“I’m going for a walk,” she said, pulling on her trainers. “I won’t be long.”

“I could use some exercise. Fancy some company?” “No, I need to practice my lines.”

“I can test you on them if you like.”

“No.” Kathy shook her head. “It’s easier on my own. I just keep reciting the speeches—the ones I can’t get my head around, you know, the ones in act two. I walk around the park, repeating them aloud. You should see the looks I get.”

I had to give it to her. Kathy said all of this with perfect sincerity, while maintaining constant eye contact. She was a remarkable actress.

My acting was also improving. I gave her a warm, open smile. “Have a nice walk.”

I followed her after she left the flat. I kept a careful distance, but she didn’t even look back once. As I said, she was getting careless.

She walked for about five minutes, to the entrance of the park. As she neared it, a man emerged from the shadows. He had his back to me and I couldn’t see his face. He had dark hair and was well built, taller than me. She went up to him and he pulled her close. They started kissing. Kathy devoured his kisses hungrily, surrendering herself to him. It was strange— to say the least—to see another man’s arms around her. His hands groped and fondled her breasts through her clothes.

I knew I should hide. I was exposed and in plain sight—if Kathy turned around, she’d be sure to see me. But I couldn’t move. I was transfixed, staring at a Medusa, turned to stone.

Eventually they stopped kissing and walked into the park, arm in arm. I followed. It was disorienting. From behind, from a distance, the man didn’t look dissimilar to me—for a few seconds I had a confused, out-of-body experience, convinced I was watching myself walking in the park with Kathy.

Kathy led the man toward a wooded area. He followed her into it and they vanished.

I felt a sick feeling of dread in my stomach. My breathing was thick, slow, heavy. Every part of my body was telling me to leave, go, run, run away. But I didn’t. I followed them into the woods.

I tried to make as little noise as possible, but twigs crunched under my feet, and branches clawed at me. I couldn’t see them anywhere—the trees grew so closely together that I could only see a few feet in front of me.

I stopped and listened. I heard a rustling in the trees, but it could have been the wind. Then I heard something unmistakable, a low-pitched guttural sound I recognized at once.

It was Kathy moaning.

I tried to get closer, but the branches caught me and held me suspended, like a fly in a web. I stood there in the dim light, breathing in the musty smell of bark and earth. I listened to Kathy moaning as he fucked her. He grunted like an animal.

I burned with hate. This man had come from nowhere and invaded my life. He had stolen and seduced and corrupted the one thing in the world that was precious to me. It was monstrous—supernatural. Perhaps he wasn’t human at all, but the instrument of some malevolent deity intent on punishing me. Was God punishing me? Why? What was I guilty of—except falling in love? Was it that I loved too deeply, too needily? Too much?

Did this man love her? I doubted it. Not the way I did. He was just using her; using her body. There was no way he cared for her as I did. I would have died for Kathy.

I would have killed for her.

I thought of my father—I knew what he’d do in this situation. He’d murder the guy. Be a man, I could hear my father shouting. Toughen up. Was that what I should do? Kill him? Dispose of him? It was a way out of this mess—a way to break the spell, release Kathy and set us free. Once she had grieved his loss, it would be over, he’d just be a memory, easily forgotten, and we could go on as before. I could do it now, here, in the park. I’d drag him into the pond, plunge his head underwater. I’d hold it there until his body convulsed and went limp in my arms. Or I could follow him home on the tube, stand right behind him on the platform, and—with a sharp shove—push him in the path of an oncoming train. Or creep up behind him on a deserted street, clutching a brick, and bash out his brains. Why not?

Kathy’s moans grew louder suddenly, and I recognized the groans she made as she climaxed. Then there was a silence … interrupted by a muffled giggle I knew so well. I could hear the snapping of twigs as they tramped out of the woods.

I waited for a few moments. Then I snapped the branches around me and fought my way out of the trees, tearing and scratching my hands to shreds.

When I emerged from the wood, my eyes were half-blind with tears. I wiped them away with a bleeding fist.

I lurched off, going nowhere. I walked round and round like a madman.