Triangular theory of love
The triangular theory of love characterizes love in an interpersonal relationship on three different scales: intimacy, passion, and commitment. Different stages and types of love can be explained as different combinations of these three elements; for example, the relative emphasis of each component changes over time as an adult romantic relationship develops. According to the author of the theory, psychologist Robert Sternberg, a relationship based on a single element is less likely to survive than one based on two or more.

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