Bowlby's attachment theory suggested that the attachment experiences of early childhood influence adult approaches to close relationships. As a result of these experiences, the child develops typical mental schemas or internal working models. The aim of this study was to analyze how young people with different attachment styles perceive the benefits and costs involved in spending as much time as possible with their partner, and to determine whether their beliefs reflect the internal working models associated with their attachment style. A sample of 1,539 university students responded to the Relationship Questionnaire (Bartholomew & Horowith, 1991), and to a questionnaire about behavioral beliefs (perceived benefits and costs). Results show that young people with different attachment styles hold different beliefs about the consequences derived from engaging in a specific behavior in romantic relationships. Secure and preoccupied individuals perceived more benefits than costs associated with the behavior, whereas dismissing and fearful individuals perceived more costs than benefits. Furthermore, secure and preoccupied individuals rated those behavioral consequences leading to enhanced intimacy or closeness more positively than avoidant individuals, whereas dismissing individuals rated more negatively those consequences that involved a loss of independence. These results confirm that a congruity exists between the beliefs associated with the behavior studied and the internal working models related to each adult attachment style.