a witness

“All these promises that we make and break--—Why is it, do you think, that people get married?”
“Passion.”
“No.”
“That’s interesting, because I would have taken you for a romantic. Why then?”
“Because we need a witness to our lives. There’s a billion people on this planet, I mean, what does any one life really mean? But in a marriage, you’re promising to care about everything; the good things, the bad things, the terrible things, the mundane things, all of it, all the time, every day. You’re saying, ‘Your life will not go unnoticed, I will notice it. Your life will not go unwitnessed, because I will be your witness.’ You can quote me on that if you like.”

from "Shall We Dance"