Why do we fall in love?

Why do we fall in love? Or why do we have to look for a life mate? I don't know if you have ever asked yourself this question, but this has always puzzled me. Some of us fall in love in an early age while others are dazzled by love much later. But just the same we fall in love, unless we are abnormal.
Love is a powerful emotion, so beautiful when your love is reciprocated but devastating when you are spurned. Love made Menelaus launched a thousand ships to regain Helen from Paris in Homer's mythical story "Helen of Troy". It made Elizabeth Browning compose her famous poem if you still remember her immortal lines, "How to I love thee? Let me count the ways." It sealed a death pact between the Shakespearean lovers Romeo and Juliet.
Love can bring magical moments when you brush elbows or shoulders with the one you love or have a crush on in high school while you share an umbrella on a rainy day and wish that that day drags on to eternity. It can make you quiver during the first time you hold hands. The narrative can be endless because love is an emotion that is hard to fathom.
But why do we fall in love? Or more precisely, why do we look for a life mate? There might be so many explanations but the closest I can come up with is less romantic - it's a basic biological compulsion to make life go on and on. Even single-cell living things are attracted to one another to make a union and reproduce. Of course, we know that creatures in the upper rung of the evolutionary chain have their own ways of falling in love and of attracting each other. But humans have the most sophisticated ways.
Unlike animals who would make a coupling act anywhere and anytime they feel like doing it, we humans have the tendency to romanticize love in the same way that we romanticize life. We don't want to live as mere reproductive machines hoodwinked by nature to procreate. And so we try to invent so many ways to shower the one we love with lavish affection.
But behind our sophistication - a nice dinner date, a token gift of roses, the soulful exchange of furtive glances and the gentle touches - lurks the basic and compulsive need to let life go on, although we always strive to rise above life's banality because behind our mundane nature we are driven by some lofty ideals that make us more than atoms.
That brings us back to the mystery of life.

Love Wins: A Book About Heaven, Hell, and the Fate of Every Person Who Ever Lived