Idk, maybe it's a classic case of "it's not you, it's me". First quarter of the book was really interesting, it hooked me right in, but then,

at about 35%, when Nick wanted to tell Olive who he really was, and of course he decided against it, and of course you knew that later on she would eventually find it out, and she would feel angry & betrayed, but would end up with him anyway - that's when I lost interest.