This thesis aims to elucidate the concept of 'Loneliness in Loving' through Hermann Schmitz's The Phenomenology of Love. This endeavor presupposes that partner love is incomplete, and as a result, love is challenging, with the act of loving inherently carrying an essence of solitude. Western philosophy since Plato has historically pursued ideals such as the soul over the body, reason over emotion, and completeness over imcompleteness. Throughout the course of philosophical history, emotions have been evaluated as inferior to reason, often seen as derivatives subordinate to the physical body. Consequently, love has established itself as a superficial notion that was difficult to perfect or reach. Considering this historical backdrop, Schmitz reinterprets the most primitive human feeling of love phenomenologically. In essence, he views the primordial love as the subject's 'affective state of surprise', 'subjective fact', and 'condensation of subjectivity'. Moreover, within the context of shared love, he perceives a duality of unity as ‘one’ while remaining ‘two,’ emphasizing the difficulty of loving. However, Schmitz simultaneously affirms love amid such difficulties. Paradoxically, he suggests that the profound loneliness of the subject make a reason for partners to personally study love. Furthermore, the loneliness in loving contributes to partners enjoying temporal and spatial freedom, facilitating the sustenance of a mature relationship. In addition, it offers the potential for insight and growth, allowing partners to transcend the limits of their own experiences. This, according to Schmitz, provides the possibility of learning and enlightenment through insight and maturity, which is crucial because the foundation of the subject’s true ‘self’ and the journey of life and maturity lies within ‘subjectivity’. This is also the reason why the subjectivity of the bodily entity is reborn from incomplete partner love to 'mutual love'. The key is to respect each other's unique identities within the world and hope for the other's maturity and well-being.