The relationship characterized by neither person being able to function without the other is known as co-dependence. In a co-dependent relationship, individuals often have an unhealthy attachment where one's identity and well-being are heavily reliant on the other person. This dynamic can lead to enabling behaviors, where one person may support the other's unhealthy habits or choices, and it can create a cycle that is difficult to break.
Co-dependence contrasts with independence, where individuals can function on their own without reliance on each other, and interdependence, which highlights a healthy balance of mutual support while maintaining personal autonomy. Dependence suggests reliance but does not necessarily imply the unhealthy dynamics seen in co-dependence. Therefore, co-dependence accurately describes the scenario where both individuals are unable to thrive without the other, pointing to a problematic relational pattern.