Although romantic partners strive to achieve an optimal balance in fulfilling both personal and relational concerns, they are inevitably challenged by how much time and effort they can dedicate to both concerns. In the present work, we examined the role of self-control in successfully maintaining personal–relational balance through promoting balance and preventing personal and relational imbalance (overdedication to personal or relational concerns, respectively). We conducted two studies among romantic couples (total N = 555), using questionnaires and diary procedures to assess everyday experiences of personal-relational balance and imbalance. Both studies consistently showed that self-control promotes personal–relational balance. Moreover, findings partly supported our hypothesis that self-control prevents personal and relational imbalance (Study 2). Finally, findings also revealed that maintaining personal–relational balance is one of the mechanisms by which self-control can promote personal and relationship well-being. Implications of the present findings and avenues for future research are discussed.