I hadn't been out long, 20 minutes or maybe half an hour but it was dark by the time I got home. I plonked the few bits I had gone to the shop for on the side in the kitchen and listened. It seemed rather quiet, too quiet really and when I went round to the front room the sofa was empty. When I had gone out they had been sitting together on the sofa. That is where I had left them and it hadn't entered my head they wouldn't still be there when I got home.

I sat down on the sofa and pulled off my boots and socks letting my feet rest on the soft red rug that covered the centre of the room. That is when I heard it, or should I say heard her, it was a cross between a groan and yelp and was accompanied by the unmistakable sound of a hand striking flesh. I lay back on the sofa and looked up at the ceiling as if maybe I might be able to see through it. The spanking sound came again and again, like a short round of applause filling the silence of the house. I smiled at the sound and my body's instant response to it, dampness between my thighs.

I didn't bother gathering up my discarded boots or socks but left them exactly where I had dropped them. In the kitchen I shoved the few perishables from my shopping trip in the fridge and left the rest sitting in the bags on the side, then flicking off the lights I made way to the bottom of the staircase.

I waited at the bottom of the stairs for a moment, listening. Had they heard me in the kitchen and stopped? Then she made a noise again, a low throaty moan and I knew if they had heard me they were ignoring my return home and carrying on. I tiptoed up the staircase and across the landing. The door to our bedroom was closed. I bent down to look through the keyhole but the angle was wrong and all I could see was my wardrobe and some of my clothes scattered on the floor where I had left them earlier in the day.

The sound of her voice made me jump

"Daddy please" she whimpered

Argghhh please what? I thought, please touch me, please fuck me, please spank me more or less or…. my imagination flitted through all these possibilities, jumping from one to another like a little series of pornographic gifs playing in my brain. Every single one of them turned me on and as I pressed my ear tighter against the door one of my hands disappeared down pass the waist band of my leggings and my fingertips sort out the hard nub of my clitoris within the puffy folds of my cunt.

She moaned again, but this time it was not accompanied by the sound of spanking, instead I could hear the rustling of sheets and the slight creak of our bed frame shifting under their weight. Our bed, I thought, they are fucking in our bed and I am out here in the dark on the landing listening to them. I should be outraged, insulted, sad, but I was none of those things. Instead I was excited, thrilled even, and my body was responding to the touch of my fingers and the sound of them together and the thoughts in my brain.

I pressed me forehead against the door, pushing against it slightly as my fingers rubbed frantically inside my leggings and my ears strained to hear them. The door can't have been properly latched because all of a sudden there was a soft click noise and I felt it give way. I watched as it gently swung open just enough for a shaft of light to come slicing through the gap between the door and the frame sending a beam of light across the landing.

I waited to see if they had noticed. Had the noise of the door been enough to alert them to my presence? For a brief moment I thought it had as there was a definite silence on the other side of the door but then it was broken with another groan, but it wasn't her this time, it was him.

"Oh yes Kitten" followed the groan.

Instantly my fingers sprang back into action and I closed my eyes and let all the dirty possible things they might be doing together play through my mind but then I realised, the light, the gap, maybe I could see now and so I inched my way over to where the door met the wall and pressed my eye up against the gap.

He was fucking her, she was pinned down on the bed beneath him, his hand holding her wrists above her head, and her legs spread wide and her head thrown back as he pushed himself into the soft flesh of her cunt again and again. In our bed, without me.

I could feel my orgasm building inside me but how could I ask, he didn't even know I was here and asking would break the moment, it would reveal me to them as