My Lover's Lover by Maggie O'Farrell
When Lily moves into new boyfriend Marcus's apartment and plunges headlong into their relationship, she must contend with an intangible, hostile presence—Marcus’s ex-girlfriend, Sinead. As Lily and Marcus become more deeply involved, Lily becomes obsessed with Sinead's fate and thinks she sees her everywhere. She must question not only her sanity, but whether the man she loves is someone she can, or should, be with at all.
"O'Farrell understands human nature in frightening depth and skillfully lays a trail of half-truths and mystery to ensnare and enthrall." - Time Out (London)
"O'Farrell's novel, written with passion and clarity, beautifully describes how old relationships can haunt new love. Spookily good."- Elle (UK)
"[O'Farrell employs a chillingly effective metaphor for the way past relationships continue to haunt the present. Wedding raw, gut-wrenching emotion to delicate, ethereal prose, she delivers a powerful psychological suspense novel filled with erotic tension." - Booklist