This is from the Spiderman 2 soundtrack(Mary refers to Mary Jane, just change it to Aerith, and New York to Midgar :P ); it reminds me of Aerith being Cloud's motivation to fight on, and how he thinks of her when Sephiroth asks him what he holds most precious, in AC. And how she's motivation to fight till the end in FF7.

You can hear the song in this video

Gifts and Curses
by Yellowcard

Mary belongs to the words of a song.
I try to be strong for her, try not to be wrong for her.
But she will not wait for me, anymore, anymore.
Why did I say all those things before? I was sure.

(She is the one), but I have a purpose,
(she is the one), and I have to fight this,
(she is the one), a villian I can't knock down.

I see your face with every punch I take,
and every bone I break, it's all for you.
And my worst pains are words I cannot say,
still I will always fight on for you.

Mary's alive in the bright New York sky,
the city lights shine for her, above them I cry for her.
Everything's small on the ground below, down below.
What if I fall, then where would I go, would she know?

(She is the one), all that I wanted,
(she is the one), and I will be haunted,
(she is the one), this gift is my curse for now.

I see your face with every punch I take,
and every bone I break, it's all for you.
And my worst pains are words I cannot say,
Still I will always fight on for you. Fight on for you ...