How do me and my to be spouse file 2023 Mortgage interest deductions if we purchased a home this year unmarried, then get married later this year?

My fiance and I have an opportunity to purchase a home very soon. We are not married and are splitting the payments 50/50. We will certainly be married before end of year. How would we deduct the mortgage payments if we bought the home unmarried but will file jointly as a married couple end of year?