I found the style - almost total dialogue, and the telling of two stories chapter by chapter to be asking too much of me as a reader. If you are only using dialogue then you have to work in so much info it can become stilted. In the end, I gave it away. I first read her book 'Things you Cannot Say' which was exceptional so maybe expected too much.
One of the best books read this year. Two stories that slowly collide. Listened to the audio version - very well read by two different readers. Many thoughtful issues touched on.