Promoting diet and physical activity is important for women with recent gestational diabetes mellitus (GDM) and their partners to reduce the risk of future type 2 diabetes (T2D). The study aimed to understand how motivation for changing diet and physical activity behaviors among women with recent GDM and their partners was experienced after participation in the Danish Face-it intervention. Fourteen couple interviews were conducted. Data analysis followed reflexive thematic analysis. Guided by self-determination theory and interdependence theory, we identified four themes affecting couples’ motivation for health behavior change: 1) The need for relatedness after delivery, 2) Promoting competence and autonomy for health behavior change, 3) Individual and mutual preferences for health behaviors, and 4) The health threat of future T2D as a cue to action. We found that the couples in general perceived the Face-it intervention as useful and motivating. Using couple interviews increased our understanding of how the women and partners influenced each other’s perspectives after a GDM-affected pregnancy and thus how targeting couples as opposed to women alone may motivate health behavior change.