The paper analyzes, in synchronic and diachronic perspective, the evolution of legal regulation of affective unions in Italy. In these terms, moving from fundamental notions of family law, the relationship between marriage and other forms of cohabitation is rebuilt, within that gradual process which, from initial concubinage penalty, expects to receive a release of different choices in the affective and family fields, through the guarantee of individual liberties in the affective field. The recent law n. 76 of 2016, in synchronic perspective, is one of the most significant outcomes of this process.