If I were to write a poem for you,
I would start off by telling you I'm sorry.
I would vaguely hint towards the things I know I must have done wrong,
I would try to take back the reasons I told you to leave,
I would love you.

Next, I'd use a metaphor to explain how you were my support beam and I was a flowering cactus.
Explain that the very way you tended to my roots and seduced my thorns was beautiful.
I would romanticize our nights together, rare but so precious.

If I were to were to write a poem for you, as I so often have,
I would do so to let the world know what was coming.
A star, that's light has yet to reach Earth but when it does it will be so bright it will shine for millennia after you're gone.
I would say, "Baby, you are not a flickering flame on a candle burning low. And this world, is not a child with ADD; you will be appreciated for your wonder, even when you have nothing more to give."

I'd also add a sprinkle of humour.
I would laugh at how our story began,
How I hated you before I met you, and the time you thought you might love me (which you still don't know I know).
I'd mention the time our friends went for each others throats, or perhaps the way we felt we could shame other poets, strip them of their title if they wrote for insults and familiar ears.

If I really were to write a poem for you,
I would want the main idea to be based on how you were the reason I write. Not just this poem but all poetry. I'd talk about how sometimes, even now, I can hear the way you dictated a phrase mimicked in my own mouth.
I would claim that we would always have words.

If I were to write a poem to you,
I would say, I forgive you.
But I will never write a poem about you.
I think, I would want too badly for you to hear it.