What was the most toxic shit you ever experienced in your life or whatever that person did to you that was so toxic

My ex best friends boyfriend is ahead on me and when he asked me to do with them and I rejected him he made her block me after like a week

Well, I used to have a girlfriend that loved me but she didn't so she basically betrayed me and said, you know, I don't love you anymore and we're over. And she basically just used me basically.