Adjusted cost basis for home sale

I live in a community property state and sold a home 50/50 joint ownership with my partner.  We separated and sold the home, and both received a 1099-S with equal sale proceeds.  I personally paid for all the remodeling upgrade costs that resulted in the increased sale market value and I expect to deduct all these expenses.   Now that we have sold the home and separated, does my partner have a way adjust the Cost Basis by reducing these home remodel upgrade costs that increased the overall fair market value?  Is this considered a gift? Thank you.