Why does my fic keep running away?

I'm just wondering what it says about me that my stories wander off and do their own thing. Aren't I supposed to be leading rather than following? 

First it was the Elle/Matt (which still bizarrely works for me even though it totally shouldn't) and now my Peter/Matt, hurt/comfort from the kink meme. It's supposed to be straight forward porn-y fun and instead Peter is being all creepy and borderline stalkery on me. It's not necessarily bad I just don't know where it's coming from :S  

Very, very odd.