LAUSR

Romantic relationships are built on trust, but partners are not always honest about their financial behavior—they may hide spending, debt, and savings from one another. This article introduces the construct of financial infidelity, defined as “engaging in any financial behavior expected to be disapproved of by one’s romantic partner and intentionally failing to disclose this behavior to them.” We develop and validate the Financial Infidelity Scale (FI-Scale) to measure individual variation in consumers' financial infidelity proneness. In 10 lab studies, one field study, and analyses of real bank account data collected in partnership with a couples’ money-management mobile application, we demonstrate that the FI-Scale has strong psychometric properties, is distinct from conceptually related scales, and predicts actual financial infidelity among married consumers. Importantly, the FI-Scale predicts a broad range of consumption-related behaviors (e.g., spending despite anticipated spousal disapproval, preferences for discreet payment methods and unmarked packaging, concealing bank account information). Our work is the first to introduce, define, and measure financial infidelity reliably and succinctly and examine its antecedents and consequences.