I love you is one of the most meaningful utterances in English speakers’ organization of intimate relationships. This thesis focuses on hegemonic understandings of I love you that are so powerful that they are rarely denaturalized or challenged, often remaining invisible or taken for granted. In order to understand the utterance and its relation to social norms, this study draws on metalinguistic commentary about the utterance on the social media platform Reddit, a popular online discussion forum. Focusing on two large communities, or subreddits, that are organized around normative gender categories, the commentary reveals a system of meaning behind I love you that is embedded in contemporary Western systems of power and norms surrounding love and romance. As shown by the data, saying I love you for the first time in a romantic relationship normatively functions as an invitation to commit to a particular kind of relationship, one which is particularly prized by society: a relationship that is moving towards a long-term, monogamous commitment culminating in marriage. This thesis examines the construction of I love you, beginning with its discursive properties as a speech act. The analysis shows that the first I love you has a performative impact, and it is also the first pair part of an adjacency pair, creating an expectation that the interlocutor will complete the pair by immediately replying, I love you too. The recipient must decide if they will reciprocate with the second pair part, and accept the invitation, or decline, and risk ending the relationship. In this sense, I love you can function as an ultimatum for a blossoming romantic relationship. The thesis goes on to illustrate the challenges involved in saying I love you, including the tensions between sincerity and timing, and how people manage vulnerability and agency. Finally, it considers strategies for dealing with those challenges, such as ways of assessing sincerity and alternatives to saying I love you too. In sum, the analysis shows that metalinguistic discussion of I love you quickly goes beyond the scope of a single utterance: it is structured by ideologies about emotion, intersubjectivity, interaction, and power. This study contributes to the line of research that examines how people produce and maintain normativity, expanding beyond normative genders and sexualities to include the powerful norms surrounding love, romance, and relationships.