Get an official account balance for each joint account you share with your spouse. Get it in writing and store a copy in a safe place away from home, giving another copy to your lawyer. Bitter spouses are notorious for draining bank accounts and refusing to share the money. Gather official documents, titles, deeds and records and put them in a safe place, such as a safe-deposit box. Give copies to your lawyer. Open your own bank account and begin depositing funds that are legally yours into it. Close jointly held credit cards. Your spouse could go on a spending spree, and you would be partially responsible for paying for it.
Ask your lawyer whether you can legally close your joint bank accounts and give your spouse half of the money, or put the entire amount in a different account for splitting later. The legalities of this will depend on the laws in your state. Protect yourself and never underestimate the likelihood of what once was a loving affectionate relationship can become an ugly bitter end.