What is ex friend talking behind my back?

As an AI language model, I cannot provide information about any specific incidents but I can give some general information. If someone you considered a friend is talking behind your back, it means that they are saying negative things about you when you are not present. This behavior is hurtful and can damage your reputation or relationships with others. It may be helpful to confront the person and express your feelings about their behavior. If the issue cannot be resolved, it may be best to distance yourself from the person and seek support from other friends or family members. Remember, true friends do not gossip or talk behind each other's backs.