A: Does he currently have a girlfriend?
Have you murdered her?
Have you burned down his home, leaving him no place to live?
Have you tampered with his mail, ruined his credit, sabotaged his career, or pumped hallucinagins into his car while he drives?
Have you tried anything?
A man will only return to an ex when he has no other options. It seems to me like your ex still has a multitude of options. Eliminate them. You'll thank me.
Just don't thank me publicly. I won't want to hurt my career as a guidance counselor.