my advice will not be "nice"
I learned from experience
open your own bank account at a bank where HE does NOT have an account
-make your password something he will never guess
-put an extra security code of the account
-make sure that you have instructed the bank that nobody including your husband can have access to the account and get it in writing
-know the routing number from your joint account and to this bank account
Get credit cards in your name.
Get rid of any joint credit cards (you may have to do this last)
Did you know that it only takes 1 person to close a joint account and take all the remaining money in it?!
Make sure the person who ever does this is YOU.
Interview all the BEST DIVORCE LAW FIRMS/LAWYERS in your area. If you speak to them first he CAN'T use them. This is important. All it takes is a 5 minute meeting and he can't hire them.
Make a copy of everything that is on your hard drive on the family computer. If he has a laptop that you have access to, copy what is on his hard drive also. EVERYTHING.
Make copies of all tax returns, bank accounts, deeds, mortgages, car lease agreements, insurance information -- EVERYTHING
If you don't already figure out what your name is on. If you rent or own is your name on the lease or papers for the house? The cable bill? Phone bill?
Take out cash and hide it.
As much as you can get away with, and don't let the kids see where you put it. Ideally somewhere you can have access to it in an emergency that does not involve entering the house.
Sorry to be such a downer but it is better to be prepared than not.
Also search the boards on this topic there were some very good lists posted a while back.