A tax refund can feel like a small windfall, which is exactly why it can become explosive when one spouse spends it first and explains later. If you filed a joint federal return, the IRS treats both spouses as jointly responsible for the return, but that does not automatically settle who owns every dollar between the two of you. The legal answer often depends on state property rules, how the refund was deposited, and whether you and your spouse had an agreement about the money.