Why do people fall in love?
What makes people fall in love?

Circumstances?
Work?
Admiration?
Sincerity?
Pity?
Don't know what else to do?
Love at first sight?

Can people fall out of love for the same reasons that made them fall in love?

What makes marriages work?

"I don't understand. How do you and mom do it?"
"Do what?"
"Stay married."
He looked at him.
"Fall in love. You keep falling in love with each other, over and over again."
(~Man and Wife)

That's beautiful advice. But so damn hard to practice.