Research has indicated that this stage generally lasts from one and a half to three years.
Since the lust and attraction stages are both considered temporary, a third stage is needed to account for long-term relationships.
Psychologist Robert Sternberg formulated a triangular theory of love and argued that love has three different components: intimacy, commitment, and passion.
Intimacy is a form in which two people share confidences and various details of their personal lives, and is usually shown in friendships and romantic love affairs.
Some historians date modern conceptions of romantic love to courtly Europe during or after the Middle Ages, although the prior existence of romantic attachments is attested by ancient love poetry.
A person can be said to love a country, principle, or goal if they value it greatly and are deeply committed to it.
Attraction is the more individualized and romantic desire for a specific candidate for mating, which develops out of lust as commitment to an individual mate forms.
Recent studies in neuroscience have indicated that as people fall in love, the brain consistently releases a certain set of chemicals, including pheromones, dopamine, norepinephrine, and serotonin, which act in a manner similar to amphetamines, stimulating the brain's pleasure center and leading to side effects such as increased heart rate, loss of appetite and sleep, and an intense feeling of excitement.
As an abstract concept, love usually refers to a deep, ineffable feeling of tenderly caring for another person.
Even this limited conception of love, however, encompasses a wealth of different feelings, from the passionate desire and intimacy of romantic love to the nonsexual emotional closeness of familial and platonic love The English word "love" can have a variety of related but distinct meanings in different contexts.
Often, other languages use multiple words to express some of the different concepts that English relies mainly on "love" to encapsulate; one example is the plurality of Greek words for "love." Cultural differences in conceptualizing love thus make it doubly difficult to establish any universal definition.
If sexual passion is also involved, this condition is called paraphilia.
Interpersonal love refers to love between human beings.