The Missing World — Margot Livesey

When an accident robs Hazel of three years of memory, Jonathan is granted the opportunity to forget the past and start afresh, to correct the mistakes in their shared past. While he begins to rewrite their history and their love, two misfits, an American and a luckless actress, travel around London, haunted by memories they'd rather forget, slowly being drawn towards Jonathan's house, where Hazel is becoming a virtual prisoner.