Losing My Best Friend to My Toxic Ex: Am I in the Wrong?

This is random, and personal, but I just had a realization. A few months ago my best friend and I stopped talking. There was an argument that I stopped and said we should come back to the conversation when my head was more clear. That conversation never continued. Days passed and I noticed she unadded me on Snapchat. But no biggie though because she wasn't respecting my wishes when it came to my toxic ex. Anyways, my realization. Me, my toxic ex, and my ex best friend, all became very close and very good friends. Things were good for awhile. But the relationship ended in a toxic way which caused me some trauma so I asked my best friend if she could at least not talk about me when she was hanging out with my ex. She did her best with it but stuff still came out, and I didn't want my ex knowing about my life because he was constantly harassing me and my family for over a year after our breakup. Eventually, my best friend, chose my ex over me and I let it happen because I was done fighting for people who didn't deserve to be in my life. She was mistreating me by going against my boundaries over and over and was believing my exes lies, said I needed help among other things. It's absolutely heartbreaking losing your best friend since middle school to your toxic ex, but I've realized it's what was best for me. I of course wish her the best, but I sadly do not want to associate with her anymore. Am I in the wrong here at all??