AITA for exposing my best friend after I found out she was secretly dating my boyfriend? I never thought I would be in a situation like this. It all started when I met Rachel at college. She was funny, charming, and instantly became my closest friend. We did everything together. I trusted her with my life. I introduced her to my boyfriend, Mark, hoping she would get along with him. They seemed to hit it off during a few group dinners, and I never suspected anything was wrong. But then I started noticing strange things. Mark would be secretive on his phone, and Rachel would suddenly go quiet when I asked about her plans. One night I decided to check his phone while he was out. What I saw made my stomach drop. There were messages between Mark and Rachel. Flirty messages, pictures, plans to meet in secret. My world shattered. I could not believe my best friend had been lying to me all this time. I confronted Mark first. He was defensive, saying it was just a fling, that it meant nothing. I felt sick. But then I decided I needed to talk to Rachel. I called her and told her I knew everything. That is when she broke down and admitted the truth. She had been secretly dating Mark for months. She said she always liked him, and when I introduced her to him, she saw her chance. I was furious. I told her she betrayed everything we stood for. She begged me to forgive her, said it was a mistake, but I could not. I decided to tell everyone at college. I wanted the world to know what kind of person she was. That is when the biggest shock happened. Mark and Rachel had planned it all. They had been working together from the start. The messages were not just between them. They had been manipulating me from the beginning. I felt so stupid. I thought I knew them. I thought I trusted them. Now I wonder if I ever knew anyone at all. I have not spoken to any of them since. I feel lost and betrayed. Did I do the right thing by exposing them? Or should I have stayed silent? I am still trying to process it all. What is your opinion?