Background Marital dissolution is ubiquitous in western societies. It poses major scientific and sociological problems both in theoretical and therapeutic terms. Scholars and therapists agree on the existence of a sort of second law of thermodynamics for sentimental relationships. Effort is required to sustain them. Love is not enough. Methodology/Principal Findings Building on a simple version of the second law we use optimal control theory as a novel approach to model sentimental dynamics. Our analysis is consistent with sociological data. We show that, when both partners have similar emotional attributes, there is an optimal effort policy yielding a durable happy union. This policy is prey to structural destabilization resulting from a combination of two factors: there is an effort gap because the optimal policy always entails discomfort and there is a tendency to lower effort to non-sustaining levels due to the instability of the dynamics. Conclusions/Significance These mathematical facts implied by the model unveil an underlying mechanism that may explain couple disruption in real scenarios. Within this framework the apparent paradox that a union consistently planned to last forever will probably break up is explained as a mechanistic consequence of the second law.

Le mathématicien espagnol José-Manuel Rey a récemment proposé une description originale de l’évolution des relations amoureuses. Ce travail, publié dans une revue prestigieuse, a...

All successful relationships are built on the same premise: The Sound Relationship House theory by Drs. John and Julie Gottman.

Peut-on croire le chercheur John Gottman quand il assure lire l'avenir dans 91% des cas? «Mon objectif? Faire comme le type qui a inventé le Velcro, a un jour confié John Gottman, chercheur et expert du mariage. Personne ne se souvient de son nom,...