Why is my ex boyfriend being like this?

When you feed a stray dog, don't be surprised when he continues to hang around your front door. This is your friend. Do you think he set the barn on fire? That is right out of the show, the Sopranos when Ralphie set fire to the barn of Tony's race horse. I would set your friend straight and tell him to go away. It sounds like you are in part to blame for his behavior, it sounds like you tolerate his clingy behavior without confronting him on it.