"Christian and Caroline Heim have written a wise and valuable book on how to make marriages last." - Roy Baumeister, President of International Positive Psychology Association Designed to be used as a companion to couple therapy, this book is based on a trailblazing study of over 1400 individuals. It presents over 75 techniques to help relationships thrive in the long-term and provides insights into the challenges faced by contemporary couples. Through in-depth interviews, this book takes pertinent questions from young couples and puts them to couples who have been together for decades. The time-tested secrets of thriving couples are presented in a new guise for a new generation. Capturing the effects of the COVID-19 pandemic, the study includes people from 52 countries and is the largest cross-sectional, multi-national study on long-term relationships to date. It highlights the dynamic and protective factors that lead to relationship longevity, as well as societal pressures, to guide therapists on how to manage these with their clients. The authors uncover how long-term relationships promote resilience, emotional, mental, and physical health, and protect against loneliness and harmful behaviours. Therapists and couples need to know what goes right in long-lasting relationships. Providing essential data and practical skills for psychologists, counsellors and other professionals, this book is a must-read for anyone working with couples to explore and understand what leads to resilient relationships in a harsh, complex world.