terambulan, that's about the worst advice I've ever seen anyone given here.
Free, whatever you do, keep within the law. You are behaving in exactly the right way. Keep yourself and your son away from this man and if possible get a restraining order, and do not, do not jeopardise yourself by attempting to deal with him physically.
It's right to fight, but there are ways and means, and so far you've done the right thing, if you hit back then he has leverage against you in the courts and worse case scenario you might accidentally kill him and end up behind bars yourself. You have a life to live now, don't do anything foolhardy and f3ck it up, and don't feel your not strong, because you are.