It is commonly known from the literature that Machiavellian individuals have negative attitudes towards people and in general towards the world´s affairs. They are distrustful of the intentions of others, and they get cautiously involved into interpersonal interactions and take risks only if that may not have any severe negative consequence. It is also a fact that there are few ventures in life that potentially involve as much insecurity and personal vulnerability as the establishment and maintenance of close relationships. In our study, we were seeking the answer to the question: do people with high levels of Machiavellianism show a generally negative, distrustful and cautious attitude in their intimate relationships, as well? What effect their pessimistic approaches have on the other consequences of the relationship (satisfaction, commitment, investment, quality of alternatives)? This question was investigated on a dyadic sample of heterosexual couples (N = 101 pairs) with Actor-Partner Interdependence Model (APIM). The results of the correlations and actor effects show that men with high levels of Machiavellianism perceive in a negative way not just people in general, but their romantic partners and relationships as well and they experience an increased level of distrust, risk, and dissatisfaction into their close relationships. Women with high levels of Machiavellianism are less negativistic and feel less discontent towards their intimate partner and relationship, but even they are unable to put their distrust and precaution aside. The results of partner effects have revealed that women's Machiavellianism undermines men's trust, while men's Machiavellianism has the effect of minimizing women's investment into their relationship.