How my fantasy ruined my relationship. 🥺

Me and my ex gf were open to kinks. She likes fem dom kind of things, but I was into c@ckolds and hotwifing. This incident happened when we were traveling on a train. We commute to college on the same train, and this train is a major place for our makeout. That day was her college function, so she was wearing a saree. She was not used to wearing sarees, but she was so damn hot in them. The train was so crowded, and we couldn't find any seats. So we stood near the door, and it was also crowded. I was standing behind her, enjoying her from the back, and she was also touching my D. But then it got even crowded, and some guy came in between us. She couldn't turn, so she didn't see that. So she mistakenly leaned on him. And he didn't waste the opportunity either. They both started enjoying each other in front of me. He was pressing her bolbs and navel and dryhuping her Gs. Half way through it, she found out it was not me. But she didn't stop. I was so hard while watching them. After alighting at the station, she told me about it, and I replied that I was watching the whole thing and was enjoying it. I thought she would be open to such incidents in the future, but surprisingly, she got angry. We went through a bad patch at that time and eventually broke up. We were both 19 at that time. I really enjoyed that moment, and I decided to marry only a girl with similar fantasies