One is Enough oleh Flora Nwapa

This is the powerful and compelling story of a woman's struggle to find an independent and fulfilling life on her own. After six years of happy, though childless, marriage, Amaka, at thirty, is shattered to discover that her husband plans to take another wife-- a woman who has already borne him two sons in secret. She makes a brave decision. Rather than stay in the comfort and security of her marital home, she will go to lagos and try to make a fresh start in life. In order to become a successful and wealthy businesswoman, Amaka finds she has to use methods as corrupt as the society in which she finds herself. Then she become involved with a catholic priest... Finally, Amaka has to decide whether she has the strength to continue alone, in the face of criticism from her family and respectability, or should she decide that 'one is enough'?