Couple therapy research identifies partner empathy as a core process for positive outcomes. The Exeter Model of couple therapy (EMCT) for depression builds on both behavioural and empathic approaches in couple therapy to reduce unhelpful couple interactions and promote mutual understanding between partners where one partner is experiencing depression. Based on EMCT, this process research study aimed to investigate mutual understanding (MU), a transtheoretical concept that refers to the moment-by-moment therapy triad talk that constructs partner empathy. Thirty-four therapy sessions from seven couples in EMCT were screened for MU events, based on pre-defined theoretically derived criteria. A discourse analysis (DA) discursive psychology approach was utilised to examine identified MU events. Specifically, participant positioning and the constructive function of discourses were examined in the therapy extracts, as these DA concepts were closely linked to MU criteria. Findings provided insights into the couple and therapist interaction sequences that contribute to MU, suggesting that both systemic-behavioural and systemic-empathic EMCT techniques can facilitate the process. Specifically, circularities, active listening tasks, and eliciting vulnerability were identified as effective techniques for MU. Findings also pointed to clients' contributions and the impact of discordant discourses. Implications for EMCT practice, and directions for future couple therapy research are discussed.