Marriage and Couples, The Gottman Institute Research

the average couple waits 6 years before seeking help for marital problems

the Four Horsemen - criticism, contempt, defensiveness, stonewalling - predict divorce 5.6 years after the wedding

emotional withdrawal and the absence of positive affect - shared humor, affection, empathy - during conflict discussions predict divorce 16.2 years after the wedding

69% of all conflict in relationships is about unresolvable, perpetual problems - based on personality differences between partners.  16% of those perpetual issues involve gridlocked couple conflict.   

https://www.gottman.com/about/research/couples/