Although marriage and cohabitation appear to be increasingly equivalent across Western countries, extensive research has demonstrated that married and cohabiting individuals still differ in terms of attitudes and well-being. Married people tend to express higher life satisfaction and more traditional opinions and values, whereas cohabiters tend to report more depressive symptoms and a more egalitarian division of tasks. Little is known about the roots of these differences. This study focus on the Swiss Household Panel subsample of respondents who lived together before they married. Its aim is to understand whether degrees of traditionalism and happiness might exist prior to marriage or, alternatively, whether it is the transition to marriage that implies changes in happiness and traditional values. Results tend to demonstrate that individuals have a high probability of responding similarly before and after the transition to marriage and validate the former hypothesis. However, results also show that the variables that play a key role before the marriage do not necessarily play the same role after. That means that marriage contributes to changing the way people assess different domains of their life as well as the hierarchy of the importance of the sociodemographic characteristics that influence individuals‘ subjective well-being, and opinions or attitudes toward family.