My Girlfriend [F18] Whored herself out. [True]

Sorry if my punctuations are not on point, English isn’t my first language. My girlfriend has been the most loyal girlfriend in the world according to me since the last three years since we have started dating. She went on to a birthday party last year which went pretty normal. Exactly a month ago, we were both really turned on and sexting. We were teasing each other, I sent her an old story of herself where she’s standing in a group with her friends from the same party. A guy seems to be so close to her ( almost grinding out her dick on her). I asked her about this and She said she enjoyed it a little bit. I got a little turned on but didn’t say nothing about it until 5 days ago when we were again sexting and I asked more. She said they didn’t even plan to do something more. She was randomly clicking pictures in the washroom (U all know girl’s habit). The washroom had a whole mirror on the outside and had two different cabins/small rooms for both male and female. She said he just came in there and started kissing her. She objected but he said “ we won’t tell anyone” and begged her to continue. They went into the female cabin, he removed her top and they intensely made out for 5-10 minutes after which he sucked her tits. She was sitting and grinding on his lap while all this happened. He made her kneel down, opened his pants and made her suck his dick. He didn’t cum but they stopped. They went on to stick together throughout the party. Here come’s the fun part. She has told me that she didnt even drink that day let alone smoke. She recently told me that she got fully drunk, got high and then made out with him. So that was a clear lie as well. I am feeling a little sad but turned on as well.