Hard to Divorce after Flash Marriage

To seek revenge, I flash-married the wealthy young heir! I'm a skilled doctor hiding my true identity. By chance, I met the heir from a prominent family. He's seriously ill, and only I can treat him. In exchange for unraveling the truth behind my parents' deaths, I agreed to a contract marriage. Little did I expect, after overcoming numerous obstacles and hardships together, I would truly fall in love with him...