How many men are obsessed with the thought of watching their wife with another man. I found a receipt from a hotel in her bag the other day, and some new sexy knickers and I was determined to see her with his cock inside her. Every detail of it. I even checked into their hotel, when I knew she would be going there, in the hope that I would at least be able to hear her moaning. I saw them arrive and eventually found they were in Room 357 - so asked at the desk whether there were any rooms near there - making the excuse that my own room was too noisy. Hearing her in ectasy has just made me more determined than ever to see them and film them.

I guess I should have known something was wrong. I was as horny as usual at the weekend when her sister and her boyfriend were doing it in the next bedroom to ours, the rhythm of the bed creaking getting faster and faster as the minutes and hours passed away, but I just couldn't get my wife interested. I had my hands down her knickers, my cock pressed between her bum cheeks, my lips down on her clit, but still she didn't get going. Then today, I discovered some soiled lace knickers in her handbag. She had been out last night, to visit her girlfriend from work, or so I thought, and I realised that while I had been getting off watching her sister doing it over the last couple of weeks, she had been getting some real action elsewhere. Now I'm haunted by the thought of where she did it, and who she did it with. Did she enjoy it? What did she wear? I want to see her with her knickers down around her ankles. I'm shocked and yet I'm excited. More excited than ever I was about watching her sister.

After the success of last Monday, I thought I'd had a setback on Saturday. My wife was at work, and I thought Anna and Paul would let me watch them again. Instead of that, when it was their "bedtime" they went upstairs instead of fucking on the sofa. Anna gave me a smile as they went upstairs together, so after a minute or so I followed them, my heart thumping with excitement as I climbed every step. But when I got to the guest bedroom, I found the door closed. I stood there, listening for every sound. I heard him say something like: "come on wear it - I want to see you on the bed in it". And when I heard the first creak of the mattress I couldn't stand it any longer. I crept onto the terrace, and climbed in through a small window leading to the shower room. I could just about see enough through the crack of the door. She was by now lying on the bed dressed in a nun's habit! And he was standing over her masturbating his cock. He opened up her black gown and started rubbing and nuzzling between her legs. It was an amazing sight. Had they done this deliberately to tease me......we were both now masturbating over the same sight. The same girl.

But I've only just discovered that my sister-in-law and her boyfriend actually like being watched. I'd schemed and planned for months about how I might get to see them fucking each other, then on Monday of last week when my wife was at work and I was left alone with the two of them, I got to know their secret - and they got to know mine. I kept glancing into the living room from the kitchen and could see his hand riding up her skirt, but it wasn't till I caught her eye that I realised she didn't mind me looking. Instead of shutting the door or taking him to her bedroom, she just looked me in the eye and got hornier with him - kissing his neck and rubbing his cock through his pants. My wife likes sex, so I don't know why it should have been such a surprise that her sister Anna was liberated as well. They knew I was watching as he lifted her t-shirt and pulled down her pants and knickers. It was excitement like I hadn't experienced before, and now I'm hooked.....

I guess I'm a voyuer. I just love watching my wife's sister having sex. It started when I heard her in the next bedroom enjoying early morning sex with her boyfriend. I had always thought she was dull and dreaded her coming to stay with us. So I just couldn't believe it was quiet Anna in the next room last month, telling her boyfriend what to do to her. Telling him to take her knickers off, and just how to lick her between the legs. It was detailed and obviously the advice of an expert. I just couldn't square the sounds coming through the wall with the shy girl I thought I knew. I could hear her telling him to "suck on it, suck on it". Our walls are not very well constructed, so I could here every move of the bed and even the sound of him kissing her down there. Ever since I've been obsessed with actually seeing them in the act......