Basically a while ago (unfortunately before I got into the habit of saving my fics) I read this one story where Sam lost his memory. I cant remember how or why. But he wakes up to Dean and assumes they're married which Dean doesnt deny. They fall in love with tons of angst from Dean who feels guilty, and then Sam finds Out they are brothers but he doesnt care, he's just afraid to lose Dean.
Castiel and Ana were involved.
and I also seem to remember that Dean had a hole done in the middle of the living room which was where he put all their hunting stuff.

Long I know, but if you could point me in the right direction I'd be very grateful.