My friend Amy recommended this book, Big Little Lies by Liane Moriarty. If you haven't already seen the TV show, read the book before you do. It was helpful to think of Madeline as Reese, Celeste as Nicole, Jane as Shailene, Bonnie as Zoë, and Renata as Laura.
Warning-it does have a few scenes that are hard to read. I normally hate violence and could get through it, but I skimmed one scene, not diving into the details.
Besides that part, it's an easy, not super deep, vacation type book. I look forward to watching the TV show now! They are winning lots of awards.