I love The Committed Marriage, by Rebbetzin Esther Jungreis! Rebbetzin Jungreis's teachings regarding how to find and maintain a loving, harmonious relationship are based on Jewish biblical wisdom, but I think that anyone could benefit by reading this book.
The book is almost like a handbook for building a better marriage and it has helped mine immensely. I have recommended it to friends and am currently reading it for the third time.
Within the pages are stories about couples in distress; we read about various situations and how they were resolved using the wisdom of the Torah and Biblical sages.
Rebbetzin Jungreis also relates stories of her long and wonderful marriage to Rebbe Jungreis, offering us insights into how to be a more considerate, loving, kind partner to our spouse. I highly recommend this book to anyone wanting to better their relationship.