Cat -so sorry to hear of your trouble. There is help out there -and the first step is to get out, which you did. Get a lawyer, which you did. Also, the money issue, you didn't say whether you owned your house etc? In Canada - even if you leave the marital residence, you can go back, change the locks and then he will have to find another place to live? Not sure where you live,but there are emergency funds available to you also, call a local woman's shelter - they have staff that can help you in this situation.
ANY type of abuse is abuse. Keep your son away from it. Keep yourself away from it. From experience i can tell you that they don't change. They use the kids as a stepping stone to get back into your life, and then abuse you again. Then you are made to feel as if it's your fault. He has issues that he has to deal with, nothing to do with you. He needs counselling-ALOT of counselling and even then - there are ways to set up visitation where you don't have to see him, through an arbitrator in the legal system. Here in Canada if the parents can't agree - the court appoints a special lawyer for the child and all these issues are worked out. Again, not sure how it works there.
PLEASE, PLEASE do not go back. I did, once and that's all it took. Suffice it to say that i am in my fourties and have 2 plates in my mouth, most of my own teeth were knocked out and had to be replaced. So PLEASE, don't believe the stories. Trust your instincts (something i wish i had done) - but he wanted to see the kids and i really didn't think he'd do anything in front of them, i was wrong. MANY years of counselling has taught me that NONE of it was my fault. He went to counselling (1 month) -and he has had 3 other relationships after me - 2 ended with an assault and the 3rd he is presently in but is showing signs of abuse (after 2 years).
There is help out there - and we are here for you too. Take care of you and your son, and let him be a man and take care of himself!