Studies have shown that the inappropriate use of in-vehicle technology may lead to hazardous disruption of driver performance. This paper reports an investigation into the socio-technical implications of maintaining a difficult conversation while driving. Twenty romantically involved couples participated in a driving-simulator experiment. The participants engaged in emotionally difficult conversations while one partner drove. The contentious conversation topics were identified using a revealed differences protocol, requiring partners to discuss sources of ongoing disagreement in their relationship. The conversations were conducted either using handsfree telephone or with both parties present in the simulator. Results indicate that the revealed differences tasks were subjectively viewed as emotionally more difficult than a control. Driver performance was found to be adversely effected for both longitudinal and lateral vehicle control. Performance was worst during contentious conversations with the partner present, suggesting the drivers may be better able to regulate driving task demands with the partner not in the vehicle during difficult discussions.