To what extent do external factors make couples vulnerable? The concern of this thesis is the role of conjugal configurations in the impact of adverse events on conjugal problems, conjugal dissatisfaction or thoughts of separation. The topic is addressed within the lives vulnerability framework. The empirical analyses are done on 721 heterosexual lasting couples from the Swiss Social Survey “Social Stratification, Cohesion and Conflict in Contemporary Families”. The analysis shows that, when controlled for the previous level of conjugal satisfaction, the bicentric configurations reinforce the negative impact of adverse events on a couple's satisfaction, while the sparse configurations reduce it. These results provide some new insight into family sociology, which has until now considered dense and supportive bicentric networks to be mainly positive regarding the quality and stability of conjugal relationships, especially compared to the sparse or interfering types of networks.