I think about anal sex while being intimate with my wife.

It happens every time. We'll be in bed, the lights low, and she'll kiss me, soft and loving. She'll touch my face, look into my eyes, and I'll feel that familiar pang of guilt because my mind is already somewhere else. As she guides me inside her, as our bodies start to move together in that familiar, comfortable rhythm, my brain betrays me.

It starts with the feeling. The warmth and the wetness are nice, but my mind starts to wonder what it would feel like to be somewhere tighter, somewhere different. I picture her on all fours in front of me, looking back over her shoulder with that mixture of trust and nervousness. I imagine the sight of myself slowly pushing into her ass, the way her body would tense and then yield.

My thrusts become more deliberate, more forceful, but I'm not really thrusting into her anymore. I'm chasing a fantasy. I'm imagining the grip, the resistance, the completely different sounds she would make—not the soft sighs I'm hearing now, but sharper, deeper gasps. My hands are on her hips, but in my head, they're spreading her cheeks apart, giving me a better view.

Sometimes I feel like a monster for it. Here is this woman who loves me, who gives me her body so freely and trustingly, and all I can think about is taking her in a way she's not entirely comfortable with, a way we've only tried a handful of times and that she's always been hesitant about.

When I finally cum, it's intense, but it's tinged with a hollow feeling. I'm picturing myself finishing deep in her ass, and the fantasy is so powerful that for a moment, I'm disappointed to come back to reality. I collapse next to her, my heart pounding, and she kisses my shoulder and whispers, "I love you."

And I whisper it back, because I do. I love her more than anything. But I can't escape the thought that the most intense part of our lovemaking for me happens entirely inside my own head.