The Competent Woman by Janette Lawler

Arlene Davis is running away from her life in Sydney. Since she was six, she has watched over her younger half-sister, Helena. Now Helena Boyd is a famous singer who also is a drug and sex addict, and it seems that Arlene is the only one who can keep her functioning. But Arlene has had enough. Helena stole Arlene’s fiancé and then dumped him. The man ended up committing suicide. Arlene has always believed her mother died when she was five. Buried memories of her past have taken her to a new life in Beckford, a small town in New South Wales, where she becomes the housekeeper for a family who live on Beckford Station. There she will watch over 14-year-old twins who have been so obnoxious to previous housekeepers that their father is desperate. The homestead causes déjà vu for Arlene and it becomes her fantasy house. Arlene discovers more than she bargained for in the town of Beckford, as she finds some long-lost relatives and old family secrets.