Unmarried cohabitation is an increasingly popular form of romantic partnership. Within the past 50 years, cohabitation has become a common experience for the majority of the European population and the number of children born within cohabitation has risen steeply. At the same time, cohabitations are relatively short-lived, and many of the cohabiting couples break up. However, the knowledge about the occurrence and consequences of cohabitation break-up is relatively scarce, especially in the European context. The aim of this dissertation is first, to map the dissolutions of cohabitating unions across European countries; and second, to research the consequences of cohabitation breakup. Special attention is paid to the new partnership formations, living arrangements and father-child relations following the union dissolution. The results of this dissertation thesis confirm that cohabitation is a less stable union than marriage, and this is regardless of a child presence. On the other hand, the consequences of cohabitation dissolution largely resemble the consequences of marital dissolution. Particularly, the living arrangements and father-child relations seem to be very similar for former cohabiting and married individuals.