The Match

I wrote a screen-play the other day.
You weren't the male lead,
I wasn't the female lead,
but it was about us.

We didn't say the things we'd say;
we didn't do the things we'd do.
The story was beautiful,
and it was mostly about us.

We were friends who both hoped for more,
and we thought we were alone in that hope,
but the audience new something different.
It was kind of about us.

I sent you a letter with a match inside;
if it scared you it could burn and be forgotten,
but if it thrilled you you could keep the match.
I thought I did it for you.

In the script you kept the match,
you passed it back when you proposed,
and we kept it on the mantle until we died,
but it was not about us.

A story doesn't work without a twist, and my metaphors weren't quite clear.
What was the match?
What was the letter?
Who was the story about?