The IRS cannot take collection action against the separate income of a non-liable spouse.
If separate tax returns are filed, only the person who signed and filed the return is legally obligated to pay the taxes. If your spouse did not sign or file a joint return with you, then the IRS cannot collect from him or her.
If joint returns were filed during a prior marriage, the IRS cannot collect your old liability from your new spouse.
Even if a joint return was filed, the IRS has innocent spouse rules to protect a spouse who claims “innocence” as to the liability. Innocence generally means the spouse did not know or had no reason to know of the liability and received no benefit from the unpaid taxes. If the IRS grants relief, it will not collect from the innocent spouse even if a joint return was filed.
The IRS also cannot take any separate assets of your spouse, like cars and real estate. However, if the asset is yours and you place it in your spouse’s name, the IRS can pursue your spouse for recovery.