The fields of demography and sociology of the family in general and of divorce and separation in particular have changed dramatically in recent years. Divorce and separation are multi-facet life-events, touching all domains of daily life: partnership, parenthood, children, siblings, relatives, social networks, activity status, income, housing, well-being, mental health, and so on. Different positions are involved: the partners, children, grandparents, lawyers, judges, notaries, counsellors, therapists, social workers, health workers and, on top of all, policy makers. The analysis of the risk factors of family dissolution is a crucial first research step. These factors refer to aspects of partnership and parenthood, the socio-cultural and social network, the well-being and mental health, the socio-economic context, and finally, the parental risk factors. The data for this project will be collected in a multi-actor perspective. The sample is based on marriage cohorts from Flanders, starting with the 1970 marriage cohort and ending with the 2004 cohort. The reason for this broad time scope is the high scientific and policy relevance of union formation and dissolution among people who are in different stages of their life course, including people who will be reaching retirement age in the years to come. People who got married at the age of 25 in 1970 will be over 60 years when we will interview them. At the same time, in the mid-1970s, divorce rates started to increase more rapidly than before, making these cohorts the first ones experiencing the consequences of the divorce boom at advanced ages. The survey is organised in collaboration with the Belgian Householdpanel PSBH (UA), the Center for Population and Family Research (KULeuven), the Center for Population, Health and Health Care (UGent) and the Center for Population and Family Studies (CBGS) (Scientific Institute of the Flemish Government). The project is financed by the Institute for the Promotion of Innovation by Science and Technology in Flanders (IWT).