Most Helpful Guy
Probably he wants to be with her and cuts contact. This is the most reasonable explanation I think.
Most Helpful Girl
I am reading this that you were already an "ex" but the guy met someone and deleted you completely from his life. If so, it is because you are an ex with no real need to be in his life, and his new girlfriend may not have liked him still having contact with you in any way, even as a contact.