Family Law Questions? Ask a Family Lawyer Online.
Your first step should be talking to your bank to see under whose authority they've frozen your accounts.
Second, you should check to see if she's involved a court, if you don't already know.
Sometimes, it is possible for one party in the marriage to ask a Judge to freeze an asset like a bank account to make sure the other party can't spend all the money before it is split in a divorce proceeding.
Generally, the Judge will still allow you to use the funds for normal life experiences, like food, mortgage, etc. Just no major new expenditures like purchasing a new car, boat or something frivolous.