<qa>  What is the number of interviews per group defined by?As appropriate for qualitative research, the number of interviews per group i.e. couples and physicians will be defined by the achievement of data saturation per group i.e. when a sense of closure is achieved because no new themes answering the research question emerged in three successive interviews; Francis et al., 2010; Pope et al., 2000; Tong et al., 2007. 