Within the past two decades there has been a growing awareness of the importance of moral and ethical judgements in family and couple therapy. In this article we provide a detailed analysis of placements of responsibility related to blame in one couple therapy session. We suggest that it is important to study therapeutic interaction in situ, when searching for an understanding of moral reasoning in couple therapy and an ethical evaluation of the practice. A detailed analysis of discursive tools used by clients and therapists makes it possible to look at moral reasoning in action as it unfolds within the flow of therapeutic conversation. The findings are discussed in relation to two discourses of moral justification: autonomy and relationality. The principle guiding the therapists' actions in the studied conversation could be called ‘relational autonomy’.