I do not know where to start. My wife is 30 years old about 5 feet tall with long black hair and she is very fit. We have been married for over 10 years and recently she has discovered something about herself - she likes a man with a very large penis. I am 15 years older than her and I am gifted with an average size penis albeit a little thinner than most I have seen. This was never an issue for us until I she saw our good friend Mike naked. Mike is about 6 feet tall with blond hair and a great toned body. He is naturally gifted with a very large penis as I discovered one afternoon after we were lounging around in the sauna. We had just finished playing squash and we headed into the sauna. When he took off his towel I really could not believe the size of his penis. He had to have been 8" soft and as thick as a toilet paper roll. I was afraid to remove my towel but I did and he just looked and smiled. Next to him, the difference was pretty scary. I knew I was on this side of average but he certainly made me question whether I had made a bad assumption all along. Later that night I told Kim about his penis in joking and it piqued her interest. She asked what it looked like. I told her he was probably about 8 inches soft and very thick and uncut. You should have seen the look on her face -- it was one of amazement. She said no way; I have never seen one that big in person ever. She suggested that we try a threesome and I said I doubt that would ever happen, as there is no way you could ever take that penis of his. She said do not tempt me with a smirk on her face. About two weeks later, we went to a pool party with a bunch of our friends. There were probably ten people there as there were 3 couples and 4 single people. After a few drinks, Mike went in swimming and as he was coming out of the pool, Samantha pulled his swimsuit down. When she did, everyone stopped. Everyone stopped what they were doing and looked over at Mike. I have never seen that look before -- it was one of disbelief combined with excitement. The silence was broken by Emily when she said "Mike put that away before someone gets poked in the eye". Mike pulled up his bathing suit but you could still see a huge bulge in his swimsuit. Right then, I felt self conscious wearing my brand new blue Speedo. Samantha was chatting with Kim and she glanced down at my Speedo. You could barely make the head and about one inch of the shaft poking through the Speedo. With her glance, you could tell she was a bit in shock but she never said a word to me -- as I learned later she did happen to mention it to the other ladies at the party. Later that night Kim and I were in bed and we were kissing. She reached into my shorts and felt my raging hard on. My penis is 5 inches long but unfortunately for Kim, it is about as thick as two of her fingers. She took off my shorts to fully expose my erection. It was rock hard and wanting to feel the warmth of her tight pussy. As she was stroking my cock, she asked if I had seen what Samantha had done to Mike at the party. I replied that everyone noticed! Kim went on to say that Mike had the biggest dick she had ever seen. As soon as she said that, the blood flow to my penis increased and I could feel my penis stiffen even further. I asked her if she was single would she like to fuck Mike. She hesitated at first and then answered that every girl at the party would fuck Mike given the right opportunity. Suddenly without warning, my penis erupted in orgasm. It caught Kim by surprise as she was just about to take her panties off. The cum dribbled down the shaft of my 5 inch cock. Kim said I cannot believe you came already. She sat there very frustrated with me and then I proceeded to kiss her pussy. She said, not now, I am no longer in the mood. With that, she turned off the lights and we went to sleep. That night was a pivotal turning point in our relationship!