Listen I have been through this on another site. Was with a girl two years married and she decided to leave. That was 5 months ago. He may be a narcissist in which case the more he knows you hurt the more he may get off on it. Appear to move on. Find someone new and watch him magically appear. These people have no empathy. You are nothing more than an object to be used.
NO one answered the question. How do you change it?