Tanya wanted to go to a party, but as I had a very long week I wasn't keen to go. In the end my wife told me that she was going anyway, with or without me. I sat in my chair and closed my eyes. The next time I opened them it was getting towards eleven p.m. and Tanya was nowhere to be seen. I decided to get changed and see what if anything of the party was still going on. The party was just ten doors away so it didn't take long to change and get there. The front door was slightly ajar so I assumed that the party was still going as I could hear loud music still blaring out. On entering the house there were just a few people in the lounge and a few more in the kitchen where the remnants of drink and food were still laid out. I grabbed a drink and wondered where Tanya could be. I wondered upstairs in case she was in the loo. She wasn't there, but what I did find were two couples in one bedroom and a women and two men in another bedroom, and they were not with their normal partners, but were all engaged in various sexual acts. I was a little shocked as I knew all of the people as they were neighbors. That left me wondering where the host was and where Tanya was. The house is of similar design to ours so I knew it had a cellar and went downstairs and went through the door. On opening the door I could hear several women groaning. The first thing I saw was the host's wife in the doggy position, on a bench of a bench press, getting her mouth fucked by one man and her pussy filled by another. It was definitely a different kind of pressing. Then moving in a little further into the room I saw my next door neighbor's wife laid on some gym mats with another neighbor hammering her pussy. Most of the noise was coming from this neighbor as she was getting plowed hard. Then I spotted my wife. Tanya was also on the mats and was riding one man as another was plugging her mouth with his cock, and a third was getting into position behind her. I heard him say, "I have been wanting this arse," for so long as he thrust slowly forward. In the eight years we have been married I had barely asked Tanya about her previous partners and what they had done. I had never dreamed that she had anal sex, but here she was about to do it anyway. Before I could say anything he was in and almost up to his balls. Tanya had taken the cock out her mouth and was groaning loudly and telling the man I had never seen before to take it easy in her arse. Then she was sucking hard again on the cock in her face. I stood there and couldn't believe that my wife was not only cheating on me, but also with three men at the same time. This was the first time that I knew of Tanya cheating on me. Albeit that I had cheated on Tanya several times I was angry yet also excited. I watched for a few minutes and then left going back to the kitchen for another drink. On entering the kitchen a woman was pouring herself another drink. She was stood in just bra and pants and looked quite sexy. As I came up behind her I reached around her for the whisky bottle. She saw my hand and cupped it onto one of her tits over her bra. Well if that wasn't an invitation I wanted to know what was. I reached around and slipped my other hand down her stomach and into her panties. The woman turned her head and groaned as she said, "Your not Ray." I told her that I could be anyone she liked. She groaned as two of my fingers slipped into her pussy and she pushed her pelvic bone at my fingers. I took my other hand from her tits and pulled her panties to one side. Then I was undoing my trousers and getting my hard cock out. Then with one thrust I was balls deep in the woman's pussy and beginning to fuck her. I never did get her name even after I dumped my cum deep in her pussy as one of the men watching us fucking, jumped in and was quickly fucking her. I grabbed that bottle and left the party with it and went home. I was soon pretty drunk and went to sleep. Next morning, with a thumping hangover, I challenged Tanya about the previous night. To my surprise she was far from repentant and instead attacked me for cheating on her. It turned out that she had known all about two of the three women I had cheated on her with and also that I had eventually turned up at the party. someone had seen me watching Tanya with the three men and had also reported that I had fucked a Mrs. Jameson. So that was who I had fucked before coming home. Tanya told me that she had been trying to tell me for months that she wanted to go swinging, but every time she got close I had gone off on something else, also the one night she was going to take me to a party I was off banging one of the women I cheated on her with. It turned out that she had gone anyway and had a great time and had come home well fucked, as had I. After we both cooled off we talked about it and Tanya said she didn't mind if I slept with other women as long as she was able to do the same. She wanted that we preferably kept it to swinging parties, but said that if I was going outside of the parties then she would to. Since that party we have attended many many more and I have learnt and awful lot about what my wife does and doesn't like and the types of men she prefers. Since that night the only cheating I have done on Tanya is at parties, but that doesn't count as she is cheating to.