One Step Too Far by Tina Seskis

Emily Coleman leaves her family behind in Manchester and starts a new life in London.  She becomes "Cat"--single, living in a house with many flatmates, and a younger new friend, Angel. What kind of trauma made Emily give up everything that made her happy? Did it have something to do with her unstable twin sister, Caroline, who's always been jealous of Emily? One Step Too Far recounts Cat's life in London and has flashback scenes from Emily's childhood and her marriage to Ben. While the book had me turning the pages to find out Emily's secret, once I knew it, I just had to groan--which makes it a little hard to recommend.