This depends on who is liable for the unpaid tax included in the offer. Assuming that only one spouse is liable such as in a liability that stems from unpaid taxes prior to marriage or the assessment Trust Fund Recover Penalty (“TFRP”), you would combine income if the taxpayers’ income pays for joint expenses and exclude the non-liable spouses assets if they are separate property or 1/2 of the joint assets if you are in one of the 9 community property States.