Not knowing your financial situation should not stop you from leaving in an emergency, but knowing about it in advance can be very helpful later.
What financial resources do you (and your partner) have?
How and where do you keep your money: In cash? A checking account? Savings account? Credit cards? Stocks or bonds? Money market? Pensions? Retirement plans?
What do you have access to? Can you withdraw money without your partner's signature? What do you have access to without your location being found out? For example, the name and location of a motel credit card charge will be on the next bill.
If you don't have access to money can you
Find a way to save a small amount for emergencies. Maybe save a little from grocery or lunch money?
Keep your valuables in a safe place where your partner will not have access to them: With a friend or relative?
Open a bank account or rent a safety deposit box?
If you have no resources or income, some of the following options may be open to you.
Applying for TANF (Temporary Aid to Needy Families) or food stamps
Filing for child support
Filing for spousal support if you are legally married
If you are undocumented but your children are US citizens, your children are eligible for services.