If you are not filing, and have never filed, a partnership return (which I presume to be the case), then you have to report the entire proceeds on your income tax return since your tax reporting statement (1099-S) was issued in your name and SSN alone.
You would then report that you received half of the proceeds as nominee for your "partner" (which, frankly, is somewhat involved and you might want to consider professional guidance).
See https://www.irs.gov/instructions/i1099gi#en_US_2022_publink1000286907
