Islands Of Mercy by Rose Tremain

A sweeping 19th-century tale that moves from genteel Bath to the jungles of Borneo, following a gifted nurse nicknamed the Angel of the Baths as she resists the prescribed destiny of marriage, enters a perilous love affair with another woman, and searches for a vocation that honors her desires; entwined with her path is that of a colonial official intent on founding a utopian outpost, whose ambitions and forbidden loves expose the entanglements of power, empire, and the price of seeking happiness beyond convention.