So, imagine yourself in a loving, committed marriage with the man who (initially, at least) made your heart melt... the father of your children... your (alleged) soulmate. 
 Now, in this situation, which is worse --- he sleeps with someone else, or he falls in love with someone else? 
 This is the basic question at the heart of the matter (har, har) of Emily Giffin's latest novel. In the beginning of the novel we meet Tessa, wife of respectable pediatric surgeon Nick and mother of two beautiful young children. Tessa has given up her own successful career to stay home with her family, and although she wouldn't change a thing she often finds herself bored and lonely. She adores Nick, but he's always so busy with work. 
 The next chapter switches to the viewpoint of Valerie, a single mom to a young boy named Charlie. While Valerie might love to be a stay-at-home mom, she spends her days practicing law and her nights devoted to her little boy. There's no husband in the picture, but she's love to find someone to fill the role of "dad" for Charlie. 
 When Charlie is involved in a serious accident, the lives of Tessa and Valerie become entwined in a way that neither may ever be the same again. 
 I really liked HEART OF THE MATTER, especially after LOVE THE ONE YOU'RE WITH, which was not my favorite. (Although, I still think SOMETHING BORROWED and SOMETHING BLUE are Giffin's best, for sure!). I enjoyed the way that the chapters alternated between Tessa and Valerie, although I found myself enjoying Tessa's parts a bit more because they were spoken from a first person perspective. I'd be interested to know why Valerie's took a third-person view, as this tended to make me side with Tessa, regardless, because I was seeing things more from her side. Was that the point? I think I'd like to see Valerie in this view as well. 
 After starting (and failing to finish) so many dull novels lately, I was glad I picked this one up. I've always been a fan of chick lit, and quite often Giffin knows exactly what to say to get it right. I'm pretty sure I'd like anything she wrote, but I think I'd give this a strong 4.5 stars if only Goodreads would allow me to do so!