Examining change in attachment in romantic couples: The role of relationship characteristics and codevelopment between partners.

Attachment insecurity is associated with important relationship outcomes, well-being, and mental health. Attachment has long been considered a stable trait, but recent findings indicate that attachment insecurity decreases over time among adults in romantic relationships. Although theoretical considerations suggest that positive experiences within these relationships should contribute to changes in attachment, little is known about the specific characteristics that foster attachment security. Using a longitudinal dyadic sample of well-established couples (N = 1,036 couples; MRelationship Duration = 8.6 years, MAge = 32.9 years), this study aims to (a) examine changes in attachment anxiety and avoidance in adults in a romantic relationship over 20 months, (b) explore the codevelopment of attachment between partners, and (c) investigate actor and partner effects of relationship characteristics (i.e., relationship satisfaction, commitment, support, closeness, responsiveness, and disclosure) on changes in attachment. Dyadic growth curve models indicated small but significant decreases in anxiety over time in women. No codevelopment between partners was observed. Further, changes in attachment were largely unrelated to baseline relationship characteristics with few exceptions: Women with highly committed and responsive partners showed weaker declines in anxiety, likely due to higher initial anxiety levels. However, changes in anxiety were negatively associated with relationship duration. These findings suggest that avoidance remains stable and uninfluenced by relationship characteristics, while anxiety decreases slightly only in women, independent of partner codevelopment. This highlights that attachment insecurity partially changes over time during the course of a romantic relationship but is largely unaffected by relationship dynamics. (PsycInfo Database Record (c) 2025 APA, all rights reserved).