Per the IRS Other Deduction Questions webpage:
Question
My spouse and I are filing separate returns. How can we split our itemized deductions?
Answer
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.
Filing a tax return with the status Married Filing Separate may limit or disqualify your eligibility to claim certain deductions or credits.
Note that any link in the information above is updated each year automatically and will take you to the most recent version of the webpage or document at the time it is accessed.