Why does this surprise you?

Everyone falls apart sometimes,
everybody hurts,
so why does it surprise you so, when I break down?

I'm not strong, I can't just carry on,
If you push me I do fall
If you cut me I do bleed
Why does this surprise you?

You can't rely on me, I can't support us both,
I'm week, I'm fragile,
I can't be the person you want me to be,
Why does this surprise you?