The Soul of Shame by Dr. Curt Thompson
Dr. Thompson is a Christian psychiatrist and brain researcher who writes really helpful stuff on how shame (as something that happens in the brain, emotions, and soul) is a disease we all have. Further, he shows how shame is the main engine that perpetuates distance in our relationships: with ourselves, with our spouses, and most importantly with God Himself. Extremely helpful for married couples to go through as a foundation for other marriage and intimacy work.
The Meaning of Marriage: Facing the Complexities of Commitment with the Wisdom of God by Dr. Tim Keller
This book is a helpful place to read about a solid theology of marriage. It helps couples understand the idea of a covenant and the safety that a covenant is designed to provide. The book addresses many cultural assumptions that we may bring into marriage, without our even knowing it, that are not part of the biblical design. (There is now also a study guide that goes with it, this could be useful for couples to go through in pairs) Link to the excellent teaching audio and slides from the Trinity Pres class taught on this book can be found here.
How We Love, Milan and Kay Yerkovich
Gives helpful categories for the attachment styles that you and your spouse may have brought into the marriage, and leads you through thinking about those differences may be affecting the connection you experience. Based on attachment theory, which we have found to be a really helpful way of looking at marriage. Talks a little bit about God's design for marriage, but is not the place to get solid theology about marriage. More of a nuts-and-bolts-of-emotional-attachment primer.
Hold Me Tight by Dr. Sue Johnson
This book walks the readers through how to developing skills to be open, attuned and responsive in order to re-establish or nurture emotional connection. Through stories, illuminating advice and practical exercises, readers will learn how to nurture, protect and grow their relationships. This book is not written from a christian perspective, but we have found it to be helpful for individuals desiring to develop healthier patterns of relating and recognize patterns that lead to disconnection.
Avoiding the Intimacy Drift by Dan Allender
This article describes the core problem in marriage, dating back to the fall of man, and describes how the gospel touches our marriages. Our tendency to hide and blame, while counterproductive to our holy desire to love, seems so appropriate in the moment of hurt. Allender unpacks this toxic dance, and conducts a new tune for us to experience intimacy reflective of Christ's death and resurrection.
Forgive and Remember, blog post by Curt Thompson
He describes the process of forgiving sin as an exercise, not in distraction from the wrong done, but in remembering it in light of the presence and love of Jesus.
Tim Keller has a series on marriage.
John Cunningham at Trinity Pres in VA does a great series called "Toward Sexual Wholeness".