I am glad you have decided to get out of the situation. Don't let threats of suicide deter you. You are not doing him any favors by staying in the relationship. He is mentally ill and needs help desperately but will not get that help while he has you to control and pawn off his own problems on. Also staying in the relationship is harmful to your son as you have already pointed out.

Find and build a support system for yourself and your child. Therapy is great but you sound so darn put together that I don't think you would be going very long. I think it will be important to gather friends and family around you to support your decision and to cry to when difficultly enevitably rises. Don't hesitate to tell your friends what is up with you. Isn't that what friendship is for?

Take care and keep us posted. We are all more then willing to be that shoulder to cry on if you need it.
Zen<font color=blue>

Deal with the difficult while it is still easy. Solve large problems when they are still small. Preventing large problems by taking small steps is easier the solving them. Therefore, the Tao person anticipates and lives wisely, by small actions accomplishing great things.--From the Tao Te Ching