How long did you know him before you married him? The first time the ex girlfriend contacted him he should of changed and blocked his number. He's mad at himself and taking it out on you. Some people can't point the
finger at themselves. Your the scapegoat. You say he shuts down and is cold and heartless. At what point does he do that?
At what point does he shut down? What type of situation are you in that he shuts down?
Sounds like he's mad at himself but is blaming you for his problems. Problems that you can't really help him with unless he talks to you about them.