AMH I know it's hard, but you seem to be slipping into an unhealthy obsession with this past relationship. Your EXBF has made up his mind and moved on.
You are clinging to the hope he'll come back as a future source of happiness, whereas you can make your own happiness if you change the direction of your thoughts.
Have you had obsessions in the past over other things? If so it might be part of your mental make-up you can work on with a therapist, or if you can't afford that, by reading as much as you can and educating yourself. I think you need some help to move on, and it's up to you to initiate it.