Take the children and get to a women's safe house.
Everything that DB and A Brown have said is absolutely true.
Sometimes, in life, we have to do what we know is right and ignore what a deeper part of us seems to "need". That "need" is leading you and your children to a very dangerous place.
Yes, you need to be seeing a psychotherapist and a psychiatrist for a proper diagnosis,medication and on going therapy. You are dealing with an addiction to this man. Only you can stop this and secure a future for yourself and your children. If you cannot think of yourself, think of them. It is not only you that is in danger. Many times perpetrators like this will kill a whole family, or they will kill what the victim loves the most.
You are incredibly intelligent and understand your situation. I believe that if you get out of this relationship, you could truely make a place for yourself in the world. This can only happen, however, if you get out of this situation now.
Again, leave NOW and go to a safehouse. Do not tell anyone where you are going. There you will find safety and all of the resources you will need to move ahead with your life. You have nothing to lose except a dangerous, unfufilling, crazily disfunctional way of living for yourself and your children.