Girlfriend wedgies

The "guy bestie" gives my gf a wedgie

I'm an 18 years old guy who has a very hot girlfriend. Her name is Sarah. She has brown hair and has a body too. We are roughly the same size but I think I'm even a little smaller than her. She is impulsive and can get really angry. We love each other but she is the boss in the relationship. 

There is one thing that I hate: she hangs out with other guys too. There is her "guy bestie" Josh, who is "just a friend". They've known each other since kindergarten. They hang out atleast once a week. I don't even know what they do together. She swears that she would never cheat on me. And I belive her. I belived. 

This happend on a wednesday when Sarah went to Josh to hang out. As usual I was upset and angry about this. When she is out with him I can do nothing but to procasinate. I was scrolling trough social media when I noticed that Sarah has posted an Instagram story. I instantly clicked on it. 

The video started. Sarah was lying on a couch on her stomach. She was wearing blue shorts and a black shirt. She looked increbibly hot. The back of her panties were showing. Josh grabbed the panties and he pulled it very high. The legholes were already showing and Josh was bouncing her up and down rapidly. Sarah was screaming and moaning and told Josh to stop in a playful voice. Josh did'nt stop until he ripped her panties. Sarah fell back to the couch and she was smiling on Josh. The boy slapped her ass and dropped the ripped panties on her. Sarah asked Josh if he is recording and he said that its only for them. Sarah then quickly went closer to Josh and she pulled on the front of his boxers. And the video ended there. 

I was really angry and I considered that cheating. The video was posted an hour ago and Sarah said that she will only go home at 7pm. 

At 7 I iMasseged her about the video. She said she tought Josh was only recording fo themselves and not for Instagram. She said that it was nothing and they do this usually. I got really angry at her. Usually? Than she got really angry at me and said that its nothing and she would never cheat on me. "We didnt fuck or kiss or anything" she typed. "Stop being so childish over a wedgie. I have to go. See u 2morrow". I couldn't belive that she just let it happen like that. 

I couldn't fall asleep for an other hour and she was online the whole time. I will question her tomorrow. I won't let this.