Partners in a relationship develop a common language and a unique set of rules and behaviours – together, they define the reality in which they exist and co-exist. Where the legal status of a relationship is not fully regulated, the recognition of the relationship’s identity is left to individual entitlements, which may not be specifically tailored to the nature of the bond. This is the case with changes in same-sex relationships. In countries where the legal status of such couples remains unrecognised, the issue governed by general administrative procedure for name changes. The paper has three aims. First, to examine the significance of adopting a shared surname in close romantic relationships, particularly in same-sex rela-tionships. Second, to explore the reasons why legislators or courts may refuse to grant a surname change in such contexts, using same-sex relationships as a primary example. This analysis leads to a broader reflection on the legal meaning of a shared surname from the perspective of regulating legal closeness. The aim of the article is not to overstate the importance of a shared surname, nor to claim that it is a necessary component of legally shaped relationality. Rather, the intention is to show that seemingly minor issues – such as surname changes – reveal underlying assumptions about relationality, closeness, and the legal understanding of family, which can significantly influence the social functioning of relationships.