How soon is too soon to get married? 'Limerence' is part of the answer. What is it?

In her latest film "Marry Me" (out Friday), Jennifer Lopez's character decides to marry a random concert-goer (Owen Wilson) she spots in the crowd. While it's a less-than-ordinary scenario, it raises the question: can marrying someone you just met end in a happily-ever-after?

While it varies from person to person, experts say how long a couple has known each other can play a factor in a marriage's success, an idea associated with the limerence theory.