My wife sarah and I had been having 3 somes with my friend Neil from work for about 6 months. Neil and i decided to ask Fat Sonia, a girl we worked with, if she wanted to join us for a party with Sarah. Fat Sonia was a dirty slut who fucked anyone. She loved the idea and agreed. 

Sarah wasn't keen when we told her that Sonia was getting involved she didn't want to share her men. She agreed because she liked the idea of another woman watching her being a total whore. Sarah said that Fat Sonia could do dildo play etc with her but no full on lesbian sex. 

About a week later Neil and I were stripping Sarah for a sex session and I messaged Fat Sonia to come over if she wanted. She came over within 15 minutes. I answered the front door to here naked with an erect cock. Sonia was amazed and I led her into the bedroom where naked Sarah was sucking Neils cock with a dildo hanging out her pussy. Fat Sonia got naked and started to play. It was insane. Fat Sonia was all over Sarah making sure she came several times. We all loved it especially Sarah, who was a sweaty cum soaked mess. 

We had many more parties and Sonia and Sarah became best friends. Sonia liked to dominate Sarah and Sarah enjoyed it.

They started to hang out together alot.

Unknown to me while I worked night shifts Sarah and Sonia would be having sex with other men, they had picked up in chat rooms or in town. They even registered on a dating site. I found out from Neil. He was on a different shift to me and they invited him over for a party. When he arrived there were 3 guys already there. He told me the next time I saw him. Apparently the 2 dirty sluts had been doing it for a while and Sonia loved to control Sarah and push her to her limits with men. He told me Sonia had several videos and pics on her phone.

I confronted Sonia and demanded to see the videos. I was shocked. Sarah was getting used while Sonia videoed and shouted encouragment.

Sonia thought it was amusing and said she loved being cruel. She could see, even though I was shocked that Sarah was cheating on me,  I was also turned on. She rubbed my hard cock and said she would show me more in her bedroom.  She told me to get naked and lay on the bed. She played me all her videos and pictures, making me masturbate as I watched. Sonia loved it, insulting me and degrading me. I loved it too. Sonia told me all the lurid adventures she and Sarah had and how Sarah loved cheating on me. Sarah would do anything for a sexual thrill. Sonia said Sarah was the dirtiest slut ever, and that was coming off fat Sonia the biggest slut anyone knew. .

We agreed not to tell Sarah I knew.  They could continue but I wanted to see videos,  pictures hidden camera footage etc and for Sonia to watch me cum while watching them and hearing the stories. Happy days.

It continued for about 9 months. Sonia was true to her word and loved to humiliate me.  In the videos she would get Sarah to insult and laugh at me as she partied with many men. The worst video Sonia produced was a gangbang. Sarah taking endless cocks in a rampant lust of DP spit roasting fisting and creampie fervour Other memorable videos were Sarah sucking 2 guys off behind a nightclub. Sonia films a car arriving at her place 3 laughing men get out followed by a naked dishevelled Sarah who goes in Sonias house for a party. 

I used to love hearing sarahs lies about just going out for a drink or to the picture house etc Sonia would have already humiliated and degraded me with the details and watched me cum. 

I just watched sarah getting her pussy and ass shaved by a new bull. He took lots of pictures of her posing nude before fucking her holes hard. He just left with her to go to his place for more fun. I am so turned on