Per IRS Publication 504 Divorced or Separated Individuals:
Itemized deductions. If you and your spouse file separate returns and one of you itemizes deductions, the other spouse can’t use the standard deduction and should also itemize deductions.
Dividing itemized deductions. You may be able to claim itemized deductions on a separate return for certain expenses that you paid separately or jointly with your spouse. See Table 1.
To report in the TaxAct program that your spouse itemized deductions:
If your spouse used the standard deduction, and you want to use the standard deduction, don't click the checkbox next to My spouse itemized deductions on their separate return. Go to our Force Standard or Itemized Deductions FAQ to make sure you have chosen standard deduction in the TaxAct program.