Diana Kirschner, a New York psychologist who ran the Institute for Comprehensive Family Therapy, says think about what happens in an extramarital affair -- teasing and flirting.
"The excitement of an affair pivots on gestures that aren't consummated -- the lingering touch, the sweet nibble on the ear, the suggestive glance that may or may not go any further," Kirschner tells the American Psychological Association.
"There is a playful novelty and uncertainty that drive up dopamine, the falling-in-love brain chemical which, in turn, creates anticipation, excitement and focus on the beloved. Infatuation sizzles."
Social media can impact romance positively and negatively. On the downside, it can become seriously addictive and time-consuming and drain energy from the relationship, Kirschner says.
"One great thing to do on Valentine's Day is to go social media cold turkey and give romantic attention to your significant other," Kirschner says in a statement.
For those who have broken up, "Be sure to unfriend your ex on Facebook and remove their photos and unfollow them on Twitter and you will move on faster."
However, social media can help a single person find romance with lost loves or by creating a large and supportive social network.
"On Valentine's Day find someone from your list of friends and celebrate," Kirschner says.