Willbwell, how are you doing? Did you get a phone for your daughter?
Putting blame on H for living your son is not going to do you any good. Yes, this is hard and your son probably suffers more than you know. Maybe you need to just tell H that your son needs his father regardless of what happens between you two, and maybe ask H to make an effort to be there for your son.
M:50 H:52 S28 (my S from previous marriage) M:17 + 3 BD: 06/12 S: 06/12 - H works in another state