Boss Affair Sank Her Promotion

AITA for exposing my best friend's secret relationship and ruining her chances at a promotion? I never thought I would do something like this, but I am so furious I cannot hold it in anymore. I will try to keep it short but the story is complicated. My best friend Lisa has always been the perfect girl. She is charming, smart, and seems to have everything figured out. I have always trusted her completely. We met in college and have been inseparable ever since. Recently, Lisa got a new job at a big company, and she was up for a major promotion. Everyone was rooting for her. But then I found out her secret. She has been dating her boss, Richard, for over a year. I saw them together at a restaurant, and I overheard their conversation. They were talking about how Richard was planning to promote Lisa if she kept quiet about their relationship. I was stunned. I confronted Lisa immediately. She begged me not to tell anyone. She said it was a mistake and that she was planning to break it off. I felt torn. On one hand, I wanted to protect her. On the other hand, I knew this could ruin her career if it came out. But then I thought about how unfair it was. She had been pretending to be single, hiding her relationship from everyone. She was willing to risk it all for a shot at the top. I decided to do what I thought was right. I leaked the story to our boss and the HR department. I sent them the photos, the overheard conversation, everything. I knew it would come out. The scandal exploded. Lisa was furious when she found out. She accused me of betraying her, of ruining her chances just because I was jealous. But the most shocking part is what happened next. Richard was fired for inappropriate conduct, but he also filed a lawsuit against the company for defamation. It turns out Lisa knew about his reputation and still went ahead with the relationship. Now she is facing not only the loss of her job but also legal trouble. And here is the twist I never saw coming. Last week, I received a message from Richard. He told me that Lisa was not just cheating on her boyfriend but was actually planning to leave him for Richard once she got the promotion. He said she had been lying to everyone including me. She was not just a victim but a manipulative person. I am still trying to process everything. Did I do the right thing? Or did I ruin her life for something she might have been planning all along? I feel betrayed but also relieved that I know the truth. I am not sure what will happen next. But I am certain that this story is far from over.