First off... GOOD FOR YOU! You were strong, made a plan and got out. That is something to be very proud of.
My husband is BiPolar, this condition has so many facets, its amazing....
Obviously he's not on meds, so you need to watch yourself. As the other poster said do not sign one single thing without reading every bit of it, and consulting with a lawyer. Since it seems uncontested you could go with a doc service, however his mental instability makes it a lot more difficult and it would be so much better if you went through a lawyer. Try to find one who is Pro Bono and also contact Legal Aid. There are people out there who will help you, you just have to find them.
Again, don't give him a thing. Don't sign anything and demand alimony so you can start over.
Be safe,