Following considerable social and demographic change over the past six decades, macro‐social theories have attempted to explain contemporary society through trends of weakening traditional institutions (e.g. state, church and family) and certainties (e.g. life‐long full‐time work and marriage) and growing self‐articulation, individualisation, destandardisation and uncertainty. At the same time, new theories and discourses on population movement have emerged, in which emphasis is placed on mobility as both an empowering personal choice and a dominant process of modernity. The contemporary ubiquity of separation, and the corresponding rise of single‐person and lone‐parent households, is often proposed as one of the clearest articulations of instability, individualisation and weakening of the family. However, through regression‐based modelling of geocoded British Household Panel Survey data, we use the compelling case of moves related to separation among families to demonstrate how: (1) links between related individuals can simultaneously trigger, shape and constrain (im)mobility; (2) linked lives can intersect in important ways with social, institutional and geographical structures; and (3) linked post‐separation (im)mobility outcomes can often contradict individually‐stated pre‐separation preferences. Controlling for a range of multilevel characteristics, we find significant gender distinctions, with fathers more likely to leave the family home than mothers, and mothers less likely to break with post‐separation familial proximity than fathers. Structural factors including housing‐market geographies and population density are found to further shape these (im)mobility patterns. Together, our empirical analysis suggests that family dissolution will rarely herald a period of heightened individualisation, self‐determination and unencumbered mobility. Indeed, a wider appreciation of the rise of non‐traditional households, their complex linked lives and associated constraints could contribute to more realistic explanations of modern (im)mobility patterns and processes.