A married couple can always file a joint return, even if one spouse does not work, or is even if they are incarcerated. As long as your spouse agrees, you can electronically sign for both of you and e-file. If you are filing by mail, you will have to take a printed copy of the tax return to your husband and have him sign it.
A step parent has the same legal position with respect to a child as a biological parent. So, the ability to claim the child as a dependent in this case, depends entirely on where the child lives more than half the nights of the year. If that is with you or your husband, or both of you, then you automatically can claim the child. If the child spends more than half the nights of the year with the other parent, then you can’t claim the child, even if it is “your year“, unless the other parent gives you a signed release form. If they don’t give you a signed release form, you may be able to complain to the family court that issued the custody order, but the IRS will not honor the custody order without the signed form 8332. Since 2023 is not a leap year, it is not possible for the child to live exactly half the nights of the year with each family. Someone must have custody 183 or more nights, and the other family must have custody 182 nights or less. You may need to keep a diary and count the exact number of nights.
