Extensive couples? literature shows that how couples feel after a conflict is predicted by certain emotional aspects of that conversation. Understanding the emotions of couples leads to a better understanding of partners? mental well-being and consequently their relationships. Hence, automatic emotion recognition among couples could potentially guide interventions to help couples improve their emotional well-being and their relationships. It has been shown that people's global emotional judgment after an experience is strongly influenced by the emotional extremes and ending of that experience, known as the peak-end rule. In this work, we leveraged this theory and used machine learning to investigate, which audio segments can be used to best predict the end-of-conversation emotions of couples. We used speech data collected from 101 Dutch-speaking couples in Belgium who engaged in 10-minute long conversations in the lab. We extracted acoustic features from (1) the audio segments with the most extreme positive and negative ratings, and (2) the ending of the audio. We used transfer learning in which we extracted these acoustic features with a pre-trained convolutional neural network (YAMNet). We then used these features to train machine learning models - support vector machines - to predict the end-of-conversation valence ratings (positive vs negative) of each partner. The results of this work could inform how to best recognize the emotions of couples after conversation-sessions and eventually, lead to a better understanding of couples? relationships either in therapy or in everyday life.