Yes, you may split your mortgage interest amount any way that you mutually agree upon such as 70/30, 60/40, 50/50, etc., as a married couple (if you live in a community state, the rules differ depending on where you live, but probably requires a 50/50 split).
"Yes, you can split the mortgage interest paid even though the form 1098 has only one taxpayer social security number.
As a married couple who co-owns the home loan and are filing separately, you can each just split the 1098 amounts (boxes 1 and 2) in your TurboTax entries for the home loan.
In other words each of your TurboTax entries will include a form 1098 from the lender that includes only your share of the interest and loan amount."
See TurboTax Expert DMarkM1's original post HERE.