Infidelity is a continuous behavior in couples throughout the history of societies, therefore it is a subject of great interest, since it directly affects the nucleus of society, which is the family itself, bringing adverse psychological consequences for the spouses and for their children that constitute collateral damage with profound consequences that usually mark their entire lives.The book pretends to know the incidence of infidelity in all factors of couple relationships; that is to say at the interpersonal and intrapersonal level; investigating and constructing the theories that emerge around this reality, the behavior of those involved and the psychological impact that this event generates both on the person who suffers infidelity and on the person who commits it.For this, it is important to know the frequency of infidelity in couples in society so that the entire community can be reached. Another aspect of interest is the causes of infidelity: psychological disorders of the unfaithful individual, pre-established mental models in this individual, deficiencies in married life, physical factors such as premature ejaculation or without any justification.After this analysis we will be concerned with proposing alternatives to reestablish relationships as a couple within the marriage and prevent the couple from disintegrating, of course in those cases that wish to integrate into this process of change and improvement by calling it somehow.This document is supported by psychological theories of human behavior and is complemented by the opinion of different authors; but mainly the basis of this work lies in the results obtained from the application of the instruments to participants who volunteered in order to contribute their experience to the analysis embodied in this work. Regarding the social impact, the family is undoubtedly the nucleus of society; but it has its beginning, its base and its continuity in the couple, therefore it is essential to provide knowledge about the causes of infidelity in order to avoid them or when the way to reconcile the parties and overcome all the psychological effects that They occur in the members of the couple and finally be able to restore an environment of healthy coexistence and love in the couple relationships that will strengthen the family and consequently the affectivity in the whole society or at least in the environment of the restored coupleThe deterioration of sexual relations as a couple due to the psychological disorders that infidelity produces in the spouses; which is analyzed in the volunteers who shared their experiences in the research presented in this book.Finally, the unknown to which we have wanted to solve from the point of view of psychology is, is there the possibility of having pleasant relationships and recovering the marriage after having suffered an infidelity?