Question: do marinette and adrien ever find out each other's identities?
Answer: Technically yes, but they don't get to remember each time! In Oblivio, Marinette and Adrien are wipes of their memories, find out their secret identities, and become a couple for a few minutes. Then they defeated Hawkmoth as Ladybug and Cat Noir and kissed before forgetting when they throw the Lucky Charm.