ex moving abroad

Hi, I'm about to receive my absolute this week! but with it seems to bring yet more problems. My ex has been seeing a woman who lives in America and he goes to see her every month, he cut the amount of child maintenance he pays ( despite a Separation Agreement) to the absolute minimum he would have to pay if i took him to the csa. When i questioned him, he said that he has amassed large credit card bills and used all his savings, and therefore he must start making savings somewhere in order to pay back his debts. His threat to me was that if he went bankcrupt i wouldn't be getting any money anyway!!
I feel that it's not his kids fault that he persued a relationship with someone that lives 10 hours on a plane away, the kids have always had dance lessons and now i'm stuggling to pay them on my own, but he refuses to help, saying that we have all had to make sacrifices due to the divorce!
Now I think he may go and live with this girlfriend and her three children, she will not leave her kids who are teenagers, but he seems to have no qualms about leaving his. To make matters worse he keeps asking his two kids if they would miss him if he goes, which is making them v upset.
If he goes and has no job to speak of over there, can i still enforce the child support somehow, I believe he would do just about anything to avoid paying it to me, even if it means deserting his kids
THANKS

Thanks for that, it's good to have information,knowledge is power and all that lol!