The attachment behavior is created in the infancy and accompanies the person throughout life. Considering that the attachment style may change, this article investigates the impact of a lasting love relationship and its influence in adults' perception of attachment to parents in the past, as well as adults' attachment to peers in the present. Using the romantic relationship as a mediator, this study assesses the correlations between the current adult attachment style to peers, as evaluated by the PAAS instrument (Portuguese Adult Attachment Scale), and the adult perceptions of their past attachment to parents, measured by FMAQ (Father and Mother Attachment Questionnaire). This research used a convenience sample consisting of 180 participants, with age between 19 and 49 years old. The results demonstrate that there are correlations between the current attachment to peers and the individuals' perception of attachment to father and mother. At the same time, however, the results show that there are differences in the correlation between the group with a lasting love relationship (G1/LLR) and the group without one (G2/WLLR). Therefore, it can be concluded from the results of this research that a lasting love relationship has the possibility to modify internal working models, as well as a person's attachment style.