Hello Sue,
The solution to your problem is to forgive your ex-husband. Yes, I know that he did awful things to you and hurt you very badly. He treated you without regard and without respect but you need to find a way to forgive him for your own sake - not for his. In this case, you also need to forgive him for your son's sake. Your son is not responsible for your ex-husband's behaviour and does not deserve to pay for it. If you cannot forgive your ex, try counselling, prayer, meditation, a new exercise activity that makes you feel good and empowered such as swimming, or just plain rebuilding your life and feeling fulfilled without him. I hope this helps. My heart is with you and your son. I am sure he has been hurt plenty by what his father did to you too. Maybe you could think of your son as your teammate, your partner in sorrow. Forgive and start living!