The Wisdom Of: Drs. John and Julie Gottman
A "couple" of relationship experts, Dr. John Gottman and Dr. Julie Gottman both teach and model how to maintain a healthy and enjoyable relationship. They are both well-established authors, therapists, and founders of The Gottman Institute.
The Gottman Institute provides a wealth of evidence-based information in the form of blog posts as well as more formal workshops and resources for purchase. Some of the topics they discuss include how to cultivate a healthy and loving relationship, how to fight effectively and even information on effective parenting practices.
If you are looking for more information on the Gottman method, the book The Seven Principles for Making Marriage Work (Gottman and Silver) is an excellent read. It breaks down the essential concepts for a successful and satisfying marriage and discusses the four most destructive behaviours that can occur during a conflict.
Alternatively, if you enjoy information in bite-sized pieces I would highly recommend signing up for The Marriage Minute. These emails are sent twice each week to your inbox and each email highlights one concept from their work that can be practically applied to your relationship.