Willard Harley
The books by Willard Harley provide valuable information about protecting your relationship by moving away from habits that inadvertently erode that sense of being in love and developing habits that cause the loving feeling to be nurtured.
Love Busters: Protecting Your Marriage from Habits That Destroy Romantic Love, by Willard F. Jr. Harley Click to order on Amazon.com
Five Steps to Romantic Love: A Workbook for Readers of Love Busters and His Needs, Her Needs, by Willard F. Jr. Harley Click to order on Amazon.com
His Needs, Her Needs: Building an Affair-Proof Marriage, by Willard F. Jr. Harley Click to order on Amazon.com
Gary Chapman
The books by Gary Chapman on love languages can be helpful to couples who feel that their attempts to show love go unrecognized. you can also visit his web site to take a quiz to identify your love language, click to take Love language quiz.
Another important quiz for couples is the apology language quiz. If you find yourself apologizing and your apology is not getting through, believed or understood, you may have an apology language barrier in your relationship. This quiz can get you started in understanding this. Click to take apology language quiz
After taking the quiz, the books can be additional resources in overcoming the language barriers in your relationship.
The 5 Love Languages: The Secret to Love that Lasts by Gary Chapman Click to purchase on Amazon.com
When Sorry Isn’t Enough: Making Things Right with Those You Love, by Gary Chapman and Jennifer M. Thomas Click to purchase on Amazon.com
Deep Relational Needs
Often couples come to me each feeling devalued in the relationship. The woman 
feeling unloved and the man feeling disrespected. This book can be helpful for couples caught in this spiral to change these patterns and more effectively meet deeply felt relational needs.
Love & Respect: The Love She Most Desires; The Respect He Desperately Needs, By Emerson Eggerichs Click to order from amazon.com
Many times couples long to connect, but have difficulty overcoming the barriers to achieving the emotional connections they desire. This book can be helpful for couples seeking to bridge these gaps. It is authored by the developer of a highly effective 
approach to marital therapy.
Hold Me Tight: Seven Conversations for a Lifetime of Love, By Sue Johnson Click to order from amazon.com
Infidelity
Infidelity can cause huge crisis and trauma in a marriage. Fortunately, marriages can recover from infidelity and if the marriage partners can face the difficult challenges of the process, can come to a place of healing and a stronger redefined bond. This book, is lengthy and takes commitment to read. However, I have found that those who are willing to take the time to read it, find it to be extremely helpful as they map out their journey to relational health.
Not “Just Friends”: Rebuilding Trust and Recovering Your Sanity After Infidelity, By Shirley Glass Click to order from amazon.com
Step Family
Introducing a ready formed family into a new marriage creates challenges that are often not anticipated. This book is a must read for couples who are either contemplating marriage where one or both are bringing children into the relationship or for those who are already married and navigating the challenges and adjustments that will happen. I have had many couples tell me that this information is extremely 
helpful and that they wished they had known it sooner.
The Smart Stepfamily: Seven Steps to a Healthy Family, By Ron Deal Click to order from amazon.com