I read this without knowing about the other book, but it worked fine as a standalone. Tristan is a troubled music producer going through a dramatic court case for custody of a child that is not even his, and Scarlett is a struggling baker who is raising her sister's son. Neither of these POV characters could really catch a break through the story - lots of heartache mixed in with the healing and romance. This was a clean romance with lots of deep themes that ultimately emphasized the power of showing up for those you love. 
To explain my 4-star rating, I should be clear that my main concern with this book is related to personal taste, and I can easily see this as a 5-star read for most people. As an identical twin myself, I couldn't get past the tired twin tropes - in a book with so much depth to explore other types of connections, I really didn't like that one twin was so unilaterally evil and that they were still confused for each other. Again, this is just my personal drama, and even while dreading any time the twin thing was brought up, I still really liked this story. I also wanted more page time for Ben (the nephew) - he felt like a realistic boy of his age from what we saw of him.