The Hardening of Helen The Gil James Chronicles

When lovely Helen's Hi-tech businessman husband throws himself out of a window to his death, she discovers he has massive gambling debts owing to some of the nastiest people in town. Family friend Gil James finds her a way of paying what she owes - while manipulating her from one appalling and humiliating situation to the next, all with an aim that would have horrified her if she'd ever even suspected what was coming...