I have a number of books that my clients find useful listed below.

Necessary Losses: The Loves, Illusions, Dependencies, and Impossible Expectations That All of Us Have to Give Up in Order to Grow
by Judith Viorst

The Road Less Traveled: A New Psychology of Love, Traditional Values and Spiritual Growth
 by M.D. M. Scott Peck

The Emotional Incest Syndrome: What to do When a Parent's Love Rules Your Life
by Dr. Patricia Love

Silently Seduced: When Parents Make their Children Partners - Understanding Covert Incest
by Kenneth Adams

How We Love:  Discover Your Love Style, Enhance Your Marriage
By Milan Yerkovich and Kay Yerkovich