The Painted Cage by Meira Chand

Marriage at twenty to an older man takes Amy Redmore from the cool green fields of Somerset to Japan, where Reggie is to take up the post of Secretary for the Yokohama United Club. Already she has learned some disturbing things about her new husband. He has a mistress by the name of Annie Luke, and a child from that liaison. Secondly he is an arsenic addict and habitually takes massive doses – more than enough to kill a normal man. But the real trouble begins with their new life on the Bluff, where the British all live in segregated splendour. Reggie is out all day with his work at the Club and at night he is lost to Yokohama’s social whirl and the temptations of the town’s notorious pleasure quarter. Amy, with her freshly awakened sense of independence finds new friends, and, more significantly, enemies – people who when the time comes will brand her publicly as an adulteress and a murderess.