Objectives: Childhood maltreatment, that is neglect and abuse, are associated with difficulties in adult relationship functioning. We tested whether childhood maltreatment changes the presence of a relationship protective mechanism, called motivated inaccuracy. It describes a decrease in romantic couples’ empathic accuracy, (EA), that is, their correct understanding of the partners’ thoughts and feelings, in situations that pose a potential threat to the stability of the relationship. With this, couples seem to protect their relationship stability from their partners’ potentially destabilizing mental contents. Method: Romantic couples were videotaped while discussing (a) their favorite film-genre (neutral/positive), (b) their most relevant fear of the past year (personally threatening), and (c) a reason that might lead to a break-up in their relationship (relationship-threatening). EA was measured by the overlap between participants’ judgments of their partners’ feelings and the partners’ self-rated actual feeling, using a continuous video rating of the interactions. Childhood neglect and abuse were retrospectively assessed by a questionnaire. Results: Overall, participants decreased their EA for each other in the relationship-threatening versus personally threatening conversation, replicating motivated inaccuracy. However, when individuals with high levels of reported childhood neglect felt threatened by the relationship-threatening condition, they did not show this relationship protective mechanism, that is, they showed maintained EA scores. Abuse in childhood did not influence the presence of motivated inaccuracy. Conclusions: Childhood neglect might influence adult romantic relationship functioning by leading to a lack of motivated inaccuracy during relationship-threatening situations. An altered threat coping strategy might cause the inability to protect oneself from relationship-threatening information.