I can't escape the madness

I've been with my N for 10 years. We have a beautiful little girl, she is 2 1/2. Since we had her he has left and come back 15 times. He leaves for about 6 weeks, telling me I dont give him enough affection and he wants to have sex with his girlfriend.

For the past 10 years I have done everything for this person, I'm so exhausted. He wont allow me to tell anyone that his not at home, he goes to elaborate lengths to make sure people think we are still together. He wont take his things just the bare essentials. He lives with his girlfriend and he says that when his sick of her he will come back, it's just so weird and matter of fact. All this time I didn't know he was a N, I just felt sorry for him and thought he was troubled and needed more, I dont know what I thought, but it was my sister about 2 years ago that said I think his a N. His new girlfriend calls him a N. Still only a week ago I was wondering if he really is one, I keep waiting for him to change. I block out so many things he has done to me its crazy..

When he leaves each time I feel like dying, then I start to feel better about 4 weeks later and as soon as I feel better he just comes back and I have no choice That sounds dumb, but it's how I feel. I'm scared of him a lot of the time.
(Mind you he wont leave me alone for one of those days, and if I dont answer the phone he'll stalk out the front of the house).

I take care of the kids he has with another women, and that women thinks he still lives with me!!! So do his kids, he stays when they come over. As compensation I suppose he gives me about 1/2 his wage every week which is a little weird, but its all spent on the kids because he wont buy anyone anything except me, weird again, it's like his buying me. I've been covering for him and lying to people for so long about what his like. He can do whatever he likes, I feel powerless. I can't breath without him asking me what Im doing. He never say anything nice and his so angry. I have a son as well who is autistic and he is the only one that see's what he does to me. I'm worried about my son. He worries about me and that's not his job.

I dont know how to escape this madness.