Bitty Schram’s character, Sharona Fleming, was one of the most important characters in Monk, yet she exited the series in season 3. Sharona was a nurse and the first personal assistant to Adrian Monk (Tony Shalhoub). While Monk was Sharona’s employer, she genuinely cared for him, and was fully aware of all his phobias and his eccentricities. At the same time, Sharona was unafraid to speak bluntly to Monk and refused to infantilize him despite the many things that make him uncomfortable.

https://screenrant.com/why-bitty-schram-sharona-left-monk-reason-explained/