Like I said, I'm waiting for scans of the novel myself to prove this isn't either smoke blowing or someone horribly misconstruing something.
And even if it's from a novel, there's a difference between first person and third person narration, and the former can be quite flawed and mistaken at times.
Then there's that glorious word I love known as Context.
EDIT: It's a Blogger's thoughts, supposedly in reaction to the book. It claims 'Lifestream Side' is about Aerith, who is a friend and lover of Cloud. It asks 'who was the pairing in the game? Was it C/A? Of course there's definitely Tifa too. And in CC, it was Z/A, right?' etc. etc.
In short, it is heresay, and may be simple smoke blowing.
Though the reaction from the C/T page suggest that it might be from the book, but is only Aerith's own opinion. IE- Cloud is to her a friend and lover. But given the Headscrew potential relating to when this is said and such, I shall again wait til book is had.