Well, your husband is wrong unfortunately. When a married couple files separate, they are each required to provide the SSN of the other on their separate tax returns. Then is because if one of you takes the standard deduction, then both of you must take the standard deduction - even if the itemized deductions of one of you is higher. LIkewise, if one itemizes deductions then you must both itemize - even if the itemized deductions of one of you is ZERO.
The IRS requires each of you to provide the spouse's SSN so they can compare and ensure both of you have done the same.
