Separating comes with a surprising amount of admin. Doing it in the right order saves repeat trips and phone calls.
Start with a list
Write down every account that has both your names on it: bank, credit cards, utilities, phone plan, insurance, streaming. Don't call anyone yet; just make the list.
Your own account first
Open a checking account in your name only and move your direct deposit there.
If you're changing your name
Go to Social Security first. Once your new card arrives, update your driver's license, then banks, then your employer.
Beneficiaries
Life insurance and retirement accounts pay whoever is listed, regardless of your situation. Check and update them.
This is general information, not legal advice. For questions about your agreement or court orders, talk with a family law attorney.