The non-institutionalised, flexible nature of living-apart-together (LAT) raises questions about partner commitment in the context of the debate about the individualisation of society. We explored how partner commitment in LAT relationships in the Netherlands is shaped by individuals’ satisfaction with, alternatives to, investments in and social support for their relationship. The underlying theoretical framework is an extended version of the Investment Model of Commitment. We conducted 22 semi-structured, in-depth interviews with men and women. The major themes that were addressed in the analysis were commitment, satisfaction, alternatives, investments, social support, relationship history and future plans. Participants were emotionally highly attached to their partner, but they doubted their commitment to maintaining their relationship in the future. Satisfaction with the current partner and intrinsic investments, such as emotions and effort, were described as contributing the most to feelings of commitment. Social support, quality of alternatives and extrinsic investments, such as material ties, were felt to contribute the least. Relationship history and life experience played an important role in how middle-aged and older individuals, of whom many were divorced, perceived the four determinants and experienced commitment. In this context, the LAT arrangement expressed fear of commitment and getting hurt, which was further reflected in limited investments. The paper concludes that although emotional attachment appears to be high among people in LAT relationships, they may have a relatively limited belief and interest in life-long partnerships.