There are many things you need to do BEFORE you leave your current situation - whether you are married or just living together.
Of course, if you are in a dangerous situation, the most important thing to do is JUST LEAVE! Your life is more important than your possessions! You can replace your stuff - you cannot replace your life!
That said, if you are able to take time and plan your exit in a calm & slow manner, this is what I have read that you should do before leaving.
It is NOT everything -- but it is a sample list of things that you should think about doing before leaving...
1. Opening a checking or savings account in your own name.
2. Leave money, an extra set of keys, copies of important documents, and extra set of clothes and medicines in a safe place or with someone that your trust.
3. Get your own post office box.
4. Find a safe place where you and your children can go or a person who can lend you money.
5. Always keep the shelter phone number and change or calling card for emergency phone calls.
6. If you have pets, make arrangements for them to b e cared for in a safe place.
What you need to take with you...
(this is not just a suggested list -- you might think of more things that you need to take with you -- if in doubt take it with you!)
Your driver's license.
Birth certificate and your children's birth certificates.
Social security cards.
Take copies of your last 5 years tax returns.
Take copies of the last 6 months of pay stubs.
Take copies of all credit cards - front & back.
(take some credit cards with you if possible)
Take copies of all checking & savings accounts for the past 5 years.
Take copies of all investment accounts - such as 401(k) & IRAs - everything you can find for the past 5 years.
Take copies of leases, car registrations, car leases, car purchase contracts, insurance papers, health insurance, medical records, etc.
Take copies of your children's school records.
Take originals (or at least copies) of legal papers -- such as all wills, trusts, divorce and custody papers -- including all TX Attorney General papers.
Take copies of all death and marriage licenses.
Take prescriptions medications that you and your children take daily.
Take all valuable jewelry -- often these things "disappear" after you leave.
Anything that is irreplaceable or an heirloom -- again this often "disappear" & or get "broken" during separation!
Take your address book.
Take all diaries, letters, cards & correspondence.
Take your computer and/or a back-up of your information & your children's on the computer.
You need to be prepared in case information "disappears" after you leave your home.
If you cannot take the originals, then make a copy of all these files & put them in a "safe" place - with a trusted friend. DO NOT PUT THEM IN THE TRUNK OF YOUR VEHICLE OR IN YOUR HOME - where these copies could be "discovered" by the other person!
I think the above list should assist you in thinking about what you need to do before you separate.