The present study explored the relationships between family of origin belonging, family peace, and marital instability among 237 married individuals aged 22–55. Data were gathered using the Family Belonging Scale, Family Peace Scale, Marital Instability Index, and a Demographic Information Form. Results demonstrated that as the level of family-of-origin belonging increased, marital instability decreased. Family of origin belonging positively predicted family peace, and family peace, in turn, negatively predicted marital instability. These findings highlight the lasting influence of early family experiences on marital dynamics and suggest that strengthening family belonging from childhood can promote marital peace and stability.