And now you all know why I don't write poetry. Because I can't write any better than Marluxia. In fact, I think that's the best poem I've ever constructed!
Come on, it has the word 'sex' in it. That gets me like a katrillion cool points.
Also, the reason Marluxia is writing is because Vexen told him that he was stupid and couldn't compose any sort of intelligent thought or literature. And Marluxia took that as a challenge.
Obviously Marly only proved what Vexen was getting at. But they are truly madly in love.