I'm not one to use a breakup poem, but if you are, here's one you could use.

Just Friends

If I could catch a rainbow
I would do it just for you
And share with you its beauty
On the days you're feeling blue

If I could build a mountain
You call it your very own
A place to find serenity
A place to be alone

If I could take your troubles
I would toss them in the sea
But all these things I'm finding
Are impossible for me

I cannot build a mountain
Or catch a rainbow fair
But let me be what I know best
I friend whose always there.