Attraction

At the end of the original jungle book Mowgli see's a girl singing and is infatuated with her and goes off to follow her, leaving behind his friends for a stranger. The end of Dragon Ball has a similiar ending, after going through many adventures and growing up with his friends, Goku grabs chichi, a girl he barely knew, and flew off together to get married and wouldn;t see his friends for years. From a certain stand point this seems absurd but when I thought about it, it is really what life is like. I have a friends I've known  for 10+ years but my post college life is already being planned around my girlfriend of less than a year. Is this just the physical attraction people have for others that makes them disregard their old life to start a new one with someone they don't know as well? Or deep down are we innately searching for love that cannot be achieved through friendship?