Falling deeply in love with someone is an all-consuming proposition. You can’t stop thinking about the person; you can’t sleep; you have no appetite. Life without this person is unimaginable, and you would sacrifice everything to be with him or her forever. Studies confirm the devotion: people in love spend more than 85% of their conscious hours thinking about their love object.

So, if true love completely takes us over, is it possible to have the same feelings for two love objects at the same time?

Some people claim that it’s not only possible but necessary, because one mate can’t possibly give them everything they need. As Aaron Ben-Zeév, Ph.D., professor of philosophy at the University of Haifa in Israel, wrote in Psychology Today, “loving more than one person at a time may not be entirely unfeasible, as the additional love would be based upon a different set of characteristics, and thus the two loves could be considered complementary rather than contradictory.”

Love Crazy Is Very Much Like Crazy

While feeling romantic love for two people at the same time seems possible on a rational level, can romantic love ever be considered rational? After all, many people are blindsided by love, which results in a kind of temporary insanity that defies attempts to assess it objectively. A person in the throes of love can even behave like someone who is mentally ill or on drugs.

A landmark study called “The Neuroimaging of Love,” conducted by Stephanie Ortigue, Ph.D., who teaches psychology and neurology at Syracuse University, found that falling in love can result in a euphoric state similar to that induced by cocaine. Dr. Ortigue’s investigation showed that, when a person falls in love, the brain releases a number of chemicals that cause euphoria. Couples who had just fallen in love also had higher blood levels of nerve growth factor (NGF), a molecule that is associated with the mutual attraction between people.

An especially interesting finding was how different types of love are associated with different parts of the brain. A mother’s love for a child and romantic love are not triggered by the same parts. Romantic love is more closely linked to brain regions involved in reward mechanisms, as well to higher-level areas that control cognitive function.

According to findings collected by Helen Fisher, Ph.D., a biological anthropologist at Rutgers University and expert on the biological basis of love, falling in love involves three stages: lust, attraction, and attachment. Here’s a brief rundown of these stages:

1. Lust. This is basic animal attraction triggered by the sex hormones estrogen or testosterone. Cognition may have a very low profile once these hormones go to work, with the desire for immediate gratification overriding concerns about consequences.

2. Attraction. Now the head starts going over the heels, spurred on by neurotransmitters including dopamine, norepinephrine, and serotonin. These hormones can render us temporarily insane, as we’re overwhelmed by desire for another that transcends mere sexual urges. Sleep, eating, jobs, and just about everything else takes a backseat to mooning over Mr. or Ms. Right.

3. Attachment. Relationships meant to last are forged during this crucial phase, and two hormones are key matchmakers. Oxytocin is released during orgasm to help promote bonding during intimacy, and secretion of vasopressin is important to long-term commitment. Suppression of either of these hormones can put a halt to one’s devotion to the love object.

Is Romantic Love a Finite Resource?

Obviously, we need to meet our basic survival needs and make a living, so we can’t devote every waking second to a love object. This devotion is therefore limited, and if there are two romantic love objects at one time, it would be difficult to determine whether that devotion were an even split between the two. Wouldn’t the one who gets the highest percentage of devotion, therefore, be the truest of the loves? And doesn’t being in love confer some exclusivity for one person over another?

There’s no clear-cut answer to these questions. My personal feeling is that you can have only one genuine romantic love at a time, but we’re in subjective territory here. If some people say they are in love with two people to an equal degree, how could we prove them wrong? At the same time, how could they prove they’re right?

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