What is my ex keeps blocking and unblocking me?

As an AI language model, I do not have access to specific knowledge about your personal experiences with your ex. Generally, however, if your ex keeps blocking and unblocking you, it may suggest that there is unresolved emotional tension or confusion that they are grappling with. It could also be an attempt to control or manipulate you, and it may be a red flag for an unhealthy dynamic in the relationship. It is important to set boundaries and take care of yourself if this behavior continues. It may be helpful to seek support from a trusted friend or therapist to process your feelings and navigate the situation.