Wow! You should be congratulated. You are doing all the right things and in very difficult situations. You are indeed a very strong person.
Others here have given you very good advice. If I could add my two cents, I would suggest a few things as well.
--Before you leave, check out a couple of shelters for abused women. Most areas have at least one. They are well versed in your rights and could probably also offer you some other good advice including assistance with legal issues and attorneys.
---On the day you plan to leave, make a very specific plan in terms of time you're leaving, route, everything.
---I know you said you don't have many people in your life. But if there is ANYONE at all you can trust, let them know and let them help you. In particular, a pastor or someone from your church could help you. In a pinch, they could help you to a shelter or even shelter you until you are safe.
---Keep a journal detailing your NH's dangerous and abusive behavior. It will help your case down the road especially as it relates to child custody and such. If he is physically abusive, document it so you have proof of these situations.
----Take all your important papers---financial, birth records, SS cards, school records, credit card numbers and passwords, medical records, insurance information, etc. Be aware of his and yours financial records, bank accounts, etc.
----Leave when it is least expected, preferably when the situation at home is agreeable and calm.
----Create a false trail. Call agencies, shelters and other organizations as far away as is feasible for your situation.
-----Take important phone numbers with you (doctors, schools, friends) as well as medications, credit cards, pay stubs, checkbooks and information about bank accounts and other assets. If possible, take titles, deeds or other property information and tax returns, copies of marriage license, wills, birth certificates and other legal documents,
----Alert school officials about the situation and make sure they know who you authorize to pick up your children.
----Reschedule any appointments that your NH is aware of when you leave.
---Use different stores and change your routine.
You have a lot on your plate and I know must be worried about a lot of things. The priority should be to keep yourself and your children safe. There are a lot of organizations to help victims of abuse. Please check into them BEFORE you plan to leave. They can help you escape your situation in a safe way. And, if possible, please try to tell someone you can trust about your situation. It's important that someone else know about the abuse you've suffered and your plans.
Best of luck to you and please let the board know, if you can, that you are safe.