Olivia
Olivia is a half-black woman who lives in England with her arranged husband, Augustus. She was married off to him in an arrangement left by her father in his will—if they rejected his idea, they wouldn't get the money, but actually, they seem to enjoy marriage in any case. Olivia thinks this is because they are in love, but technically, it's because Olivia is the "other woman." Augustus is already married, and he is using her.
Augustus
Augustus is Olivia's cousin and husband. Because his uncle is Olivia's father, the only way he can get the large inheritance left to him in his uncle's will is to marry his cousin, so he does. There's just one problem—he's already married. He lies to everyone, claims his wife is dead (she isn't) and then, when Olivia arrives, he marries her and lets her fall in love with him. He leaves her in the dark.
Dido
Dido is a Jamaican woman who works for Olivia as a maid. She is family to Olivia—closer family than her own father, it seems, or than her husband who lied about everything to use her for sex and money. Only Dido cares about Olivia as a person, and when Olivia realizes that she's burnt out of her own culture's mistreatment, she goes with Dido to Jamaica to make a new life there.
Mr. Honeywood
Mrs. Honeywood's son whom Olivia meets on the boat on her way to England. Mr. Honeywood is impressive and attractive, but after the fallout from her faux-marriage, Olivia is too devastated to pursue any relationship with him. Her ability to connect with "Honeywood" is damaged when she learns she has been used by her husband.