If you want "protection" without filing anything yet... all you have to do in california, is basically live separately.

Then if anything major comes up, you file legal separation, andyou can retroactively state that the "separation date" is the time that you started living separately.

Any debts that he incurred after that date, that you dont put your name on... are then solely his.

however, IANAL (I Am Not A Lawyer)

My current status: june 2006. Wife ran out and filed D.
Finalized Jan 11, 2010, after 12.5 years M.
3 wonderful sons caught in the middle