This paper examines the causal relationship between marriage and subjective well-being using a 17-year longitudinal dataset from the German Socio-Economic Panel. The authors find evidence that happier singles are more likely to marry, and there are significant differences in the benefits of marriage across couples. Potential and actual division of labor, especially for women and families with young children, contribute positively to spouses' well-being. In contrast, large differences in educational levels between partners have a negative impact on life satisfaction. The study also reveals selection effects, where happier individuals are more likely to marry, particularly those who marry at a younger age. The findings suggest that marriage can enhance well-being, but the extent of benefits varies depending on factors such as labor division and educational compatibility.This paper examines the causal relationship between marriage and subjective well-being using a 17-year longitudinal dataset from the German Socio-Economic Panel. The authors find evidence that happier singles are more likely to marry, and there are significant differences in the benefits of marriage across couples. Potential and actual division of labor, especially for women and families with young children, contribute positively to spouses' well-being. In contrast, large differences in educational levels between partners have a negative impact on life satisfaction. The study also reveals selection effects, where happier individuals are more likely to marry, particularly those who marry at a younger age. The findings suggest that marriage can enhance well-being, but the extent of benefits varies depending on factors such as labor division and educational compatibility.