Per Other Deduction Questions from the IRS:
My spouse and I are filing separate returns. How can we split our itemized deductions?
If you and your spouse file separate returns and one of you itemizes deductions, the other spouse must also itemize, because in this case, the standard deduction amount is zero for the non-itemizing spouse.
- You may claim itemized deductions on a separate return for certain expenses that you paid separately or jointly with your spouse.
- When paid from separate funds, expenses are deductible only by the spouse who pays them deductible by the spouse who pays them.
- When expenses are paid from funds owned by both spouses such as from a joint checking account or an account that is considered community property under the laws of the state in which the spouses reside, you should generally split the deduction between you and your spouse.
Please be aware that filing a tax return with the status Married Filing Separate may limit or disqualify your eligibility to claim certain deductions or credits.