This dissertation investigates the role of prior relationship experiences and children in how people form new relationships, or ‘unions’, referring to those where partners live together. For many people, union formation is not a once-in-a-lifetime event, but something they experience multiple times and in different stages of their life. As such, many singles in the so-called ‘partner market’ have lived with and split from a partner before, and some have children. This research shows that prior relationship experiences and children shape the process of union formation in several ways, including by limiting commitment to a new partner; motivating living-apart-together (LAT); lowering the chances of LAT couples moving in together; reducing the...