My wife Karen has been the PA to Jack her boss for about 18 years. She has been working for him since she was 22. I married her when she was 23. Karen has a slender body with 36d tits and her pussy is always completely smooth. She has kept her figure even after having out twins, who are now 16 and can be trusted when we leave them at home when we go away. Jack has been a widow for the last 5 years and is aged 62 and keeps fit with regular golf days. I have had my suspicions that he has been having sexual favours from Karen for the last couple of years but have never approached her about it. Jack invited us to his Villa last week in Marbella. We went but I had reservations why he wanted us both there. We ended up on a beach on the second day where Jack took us for as stroll and I soon realised it was where everyone went naked. We had brought towels and swim wear. Jack found a spot towards the back of the beach near the dunes and we spread our towels out. He then stripped naked in front of us. Karen did not looked surprised when he stood there with 5 inch member swinging about in front of her. She said she was only going topless and encouraged me to strip off. I took off my clothes and laid face down on my towel. Jack laid on his back and I saw his prick was semi hard. After about 30 minutes he asked to go for a walk in the dunes with him as he wanted to have a chat. We went off both naked. he did not speak but led me around some dunes and bushes. We then moved slowly upon a clearing and he told me to look over the top of the low shrub. I peered over and saw a buxom blond on her back with a bloke in between her legs sucking away at her clit and pussy. I had never seen anything like that before and just stood and watched. The woman started to moan and her body bucked as she came. The bloke moved up to her head and offered his prick, which she sucked to erection. She then turned over on all fours and the bloke fucked her doggy style. After a couple of minutes he slapped her arse and appeared to come up her. I looked over and saw Jack wanking his erect 8 inch prick. The bloke and the woman then laid on their backs. Jack Said\"Come on show\'s over\" He asked what I thought about what I had just seen and noticed I had got an erection. I told him it was very sexy watching someone else fuck out in the open and in the sun. He then asked if Karen and myself would put on a show for others in the dunes. I told him I doubt if Karen would do it and I would not maintain an erection in front of others. He said \"Lets see what Karen thinks about it\". We got back to Karen and I told her what we had just watched and Jack\'s suggestion. Jack had walked down to the sea to have a dip. Karen then said \" Roy, how do you think we have had all the expensive holidays over the last couple of years. Jack pays me extra for me to suck him off and I let him play with my tits and finger me. He now whats to fuck me but with your approval and this is one of his fantasy\'s. He would also like a threesome either with you or another male with him and me\". I was shocked, but could see in Karen\'s eyes she was up for it. Things raced around my head and I thought of all the first class holidays we had had lately.I told to go off into the dunes with him, I would follow a few minutes later. Jack came back, Karen stood up and took off her bikini bottom and said to Jack \"Lets go and play\". I watched them walk off up into the dune area. I sat down and wondered what I had done. I suddenly realised 15 minutes had gone by. I jumped up and ran into the dune area. I had no idea where they had gone. I looked over and 3 blokes standing looking over a shrub. I made my way over to them and then noticed they were all wanking their pricks. I got to the shrub, looked over into the small clearing and saw Jack saw fucking Karen doggy style and the saw another bloke lying under Karen. He appeared to be licking her clit while she sucked him off. Jack looked over to me and said\"Could\'nt wait for you Roy, so we started without you\". The bloke under Karen then bucked as he came in her mouth. She opened her mouth and let his spunk run back down his shaft and balls. Jack withdrew and he came over her back. I noticed one of the three males walk round into the clearing. Karen got on her knees and indicated for him to come over her tits. Within a minute he appeared to gush pints of spunk over her tits. I must admit it was a beautiful site seeing Karen being fucked and acting like a whore. Over the next few days first Jack would take Karen up into the dunes, spend some time playing with her and then fuck her. He would come back to the beach and I would go up play with and then fuck her. Most of the times when either Jack or I were with her we had an audience of 4 r 5 blokes and usually Karen would suck at least two of them and the remainder wank off over as she lay on the ground waiting for either Jack or myself to turn up. Jack has now invited us back in August with a few of his golf buddies. Karen reckons she will be asked to be the slut for a gang bang with at least six blokes. So on the strength of last week we are flying to Dubai next week for 5 days courtesy of Jack.