Who pays the bills while we're separated?
Absent an order, the obligation usually follows the paperwork. Whoever signed for a debt still owes it, regardless of who is living in the house or who moved out. Your lender does not know you have separated and would not care if it did. The nine community property states work differently: debt taken on during the marriage is often community debt, reachable against either spouse whatever the account says.
What a court eventually decides about who bears those costs is a separate question, settled later, and often adjusted retroactively in the final division.
The default nobody tells you
Keep paying what you have been paying. It is dull advice and it is right, for three reasons.
It protects your credit, which is the thing quietly most at risk in a separation and the slowest to repair. It preserves the asset, since a house heading toward foreclosure is worth less to both of you. And it reads well: the spouse who kept the household running while things were resolved is in a stronger position than the one who stopped paying to make a point.
Stopping unilaterally is the move that looks like leverage and functions like self-harm.
Getting it decided properly
Temporary orders are the tool. Once a case is filed, either spouse can ask the court to set who pays what while the divorce is pending, including the mortgage, utilities, insurance, and support for a lower-earning spouse. This is routine, and people wait far too long to ask for it.
If money is being used against you, ask early. Courts can order interim support and, in many places, order the better-resourced spouse to contribute to the other's legal fees. That request usually has to be made rather than volunteered.
And if money is being controlled or withheld as a way of controlling you, that is financial abuse, and it often travels with other kinds. You do not have to wait for a scheduled hearing. Emergency protective orders can be requested immediately, and in many states can cover exclusive use of the home and temporary support. Talk to an advocate before you change accounts or move money, because the timing of those steps matters for your safety and not only for your case. The safety resources page has the numbers, free and confidential at any hour.
A written agreement works too if you can reach one. Put it in writing, including who pays which account and for how long, and revisit it if either income changes.
Contributions are usually tracked
An important reassurance for whoever is carrying more.
Payments made during separation on marital debts are commonly accounted for in the final division. If you paid the mortgage alone for eight months on a house you both own, that generally does not evaporate. Equally, if one spouse lived in the house rent-free while the other paid for it, courts can take that into account too.
So keep records. Which accounts you paid, when, and how much. A simple spreadsheet is enough, and it is worth far more than trying to reconstruct a year of payments from memory later.
What not to do
Do not run up new debt expecting it to be shared. Spending during separation invites an argument about whether it benefited the household or only you.
Do not close accounts your spouse depends on without notice or agreement, particularly anything the children rely on. It escalates fast and it looks punitive. In the states with automatic restraints it can also be a breach of a standing court order rather than just a bad look, so check whether one is in force before you touch anything. Those orders are not as total as they read. In California, which set the pattern, they let you go on paying for the necessities of life and the ordinary running of things, and they let you use marital or separate money to hire a lawyer, so nobody should stop paying the mortgage or decide they cannot afford counsel because of one. What they restrict is the unusual: there you owe your spouse five business days' notice before an extraordinary expense, and an accounting to the court for it afterward.
Do not empty a joint account to cover your new place. That has its own consequences, and being the one who did it is worse than being the one it happened to.
Do not assume a decree fixes the past. Your creditors are not bound by it, so a card left open in both names remains both your problem no matter who was ordered to pay it. The court's answer and the bank's answer are different.
If you are still under one roof
Different practicalities, same principle. Living together while you separate covers running one house as two households, including the money side.
Whether interim support is available, how contributions during separation are credited, and what temporary orders can cover vary by state. If you are carrying the household alone or being cut off from money, that is worth raising with a licensed family-law attorney sooner rather than later.