Relationship patterns before and after pathological gambling were investigated qualitatively using eight in-depth clinical case studies in which one partner met Diagnostic and Statistical Manual of Mental Disorders-IV pathological gambling criteria. Five circuits of couple interactions are described: (i) fault-lines; (ii) pressure points; (iii) escalation; (iv) relapse and (v) congruence. The exploration of these circuits is developed in two complementary articles. This first article delineates the first four circuits as recursive self-perpetuating cycles of couple distress in systemic interaction with pathological gambling development and relapse. The second article delineates how a couple can be helped to extricate themselves from these recursive circuits through ‘congruence’. Implications of this relational formulation of pathological gambling for conceptualization, assessment and treatment are discussed.