See https://www.thetaxadviser.com/issues/2022/dec/tax-planning-issues-assisting-clients-in-a-divorce.htm...
and
https://www.law.cornell.edu/uscode/text/26/1041
Your adjusted basis should be the adjusted basis in the hands of your ex-husband plus any improvements you made after the transfer.
Given the scenario you presented here, you should probably seek guidance from a local tax professional.
