<P> Charlotte and Cooper enter into a relationship , but break up when he discovers that she is opening a new practice to rival his own , on the fourth floor of the same building . They come close to reconciling when Charlotte believes she may be pregnant , but she is disappointed when her pregnancy test comes back negative and Cooper subsequently rejects her again . They re-unite when Charlotte 's father dies from lung cancer , and Cooper helps her to turn off his life support machine . Charlotte is jealous of Cooper 's relationship with his best friend Violet Turner ( Amy Brenneman ) , particularly when he opts to move in with her to support her through her pregnancy . In retaliation , Charlotte sleeps with Archer Montgomery ( Grant Show ) ; however , Cooper forgives her as he realizes she is afraid of being in a committed relationship and is trying to push him away . Charlotte is later fired from her position as director of Pacific Wellcare as the practice owner , William White ( James Morrison ) , believes her to be heartless . However , she continues private practice work as she is employed to replace Naomi at Oceanside Wellness , electing to practice sexology as her specialty . </P>
when do charlotte and cooper get back together
when Charlotte 's father dies from lung cancer