I am talking about my time in high school (Im 22 now). There was a girl in my class I didn‘t like at first but the more time I spent with her the more feelings I started to catch. Time flew by and we admitted to each other that we share the same feelings. For me actually it was clear that I wanted her to be my girlfriend and I communicated it to her and she kept me waiting.
In this specific time span there was a big party. On this evening she kissed another guy and a girl. I was only 16 so this was for me the most heartbreaking moment I could ever imagine. Even though we were not officially together I felt really betrayed because this is something my loyalty never would have let me do and I had no understanding for this behavior. 
Next day she apoligized blaming she was too drunk she could not handle it if I would turn my back on her. After a week I forgave her.
She suddenly wanted to be my girlfriend and so it happened.
After just thee months she broke up with me. She told me I was too controlling. In fact I was because she kept going on these parties and get drunk and my trust was not fully recovered.

One half year later we went on a trip. Me, some classmates and her included. Our relation after the break up was „normal“. We still hang together and I had the feeling that she was still into me. Me too kinda. We all shared one room together (we were 8 ppl)

After the first night in this city (Hamburg) I met a spanish girl. After a short while it was all clear were it was heading. Her appartment was way too far and mine was just around the corner. For me it was a very exciting moment because I was about to lose my virginity (I did not have sex with my ex). 

We went to my appartment and the security let us in even though he actually wasnt allowed to let strangers in but he was aware of the situation and just winked me in. I told the spanish girl of the situation and made to hear clear that if somebody is already inside sleeping we would have to be very quite. We entered in and my ex and 2 friends of her were already sleeping. I took the girl and went with her in my bed and had sex for about a half hour. The room was very small and if they would have woke up they could easily see us. But I did not care because I really wanted to have sex with this girl. Revenge was not my goal actually but I thought cmon I have not done anything wrong to her so why should me bother this.

The spanish girl did not want to go home after the hook up and slept beside me. The very next morning I woke her up a little earlier while every one was sleeping and told to her that she has to go. Just about she was to leave my ex and her friend woke up. She was so confused and angry. I left the room with the spanish girl and I heard as soon as I closed the door „Is he fucking serious?“. Later she told me that she is really hurt of what I did and stopped talking to me for about 2 months. She said that she thought we would come back together. But we did not. 