Tax on Sale of Rental Home without 1099 by two unmarried people

Me and my (unmarried) partner bought a rental home in 2019, and sold in 2024. We did not receive a 1099 form, and we split the proceeds. We did not live in the house at any time.
My partner claimed all rental income prior (I received none in agreement it would go mostly back into the house itself). After the sale, we were issued separate checks by the agent for the profit.

How would we file to indicate that the proceeds were split, as there was no 1099 indicating a 50/50 split?

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