The book wants to play with the reader's mind and allows that desire to override anything else. It does start out very strong. But the first big reveal of what happened and its excuse for things does not quite work. It made me think of The Perfect Girlfriend, which handles the unreliable narrator issue far better. Good start, weak middle and horrible finish.
(BTW, I do not usually do this, but I strongly advise against reading this if you cannot have children or suffer from a mental illness).