I wish I could give you a great big hug right now. This is going to be a very difficult time for you. Unfortunately your almost ex is going to make it as difficult as possible. It's in HIS best interest to do so.But what is YOUR best interest? Or you CHILDRENS best interest? At this point him not talking to you is the absolute best thing that can happen. If he's not talking to you, you cannot listen. If you are not listening, then he cannot manipulate you. Will this be difficult and painful? Absolutely, that's what he wants it to be. He wants to confuse you, scare you, and make you feel bad, or more likely, guilty. If you feel these things, he get's his way. Try and get MAD instead. It's when people are angry that they take action. Ask yourself these questions:
Why should you bear all of the financial burden and responsibility of raising your children, while he gets only rewards?
Is it OK that he threatens you and makes you feel pain, so that he can get his way?
Is it OK that your children will bear the biggest burden of his selfishness, by have only one parent supporting them?
Are you OK with being the one to always tell them no, when if you had the support you could tell them yes?
Are you prepared to work full time, paying a great big chunk of your hard earned money, to a child care provider, who will probably see you kids more than you do, so that you can go to that job, while your ex, gets to keep all of his money, and do what he wants with it?
You have gotten some great advice, especially from Kristina H. and Susan B. Take it! No matter how ugly this gets, and it will get ugly even if you don't want it to, you MUST MUST MUST get a lawyer and fight. Fight for your rights, fight for your dignity, fight for your self respect, fight for your children, and fight on YOUR OWN TERMS! You need the court to order child support for your children. If he doesn't pay, the only way it will be taken from his paycheck is if the support is court ordered. If it's a verbal agreement you will have to go back to court and get the order anyhow, so do it the first time.
I am not a particularly religious person, but I will be praying for you on this difficult journey.