I read this pre-slash (kind of fluffy?) fic where House and Wilson discuss Holmes and Watson, but I don't remember what it was called so I'm having trouble finding it again.
House and Wilson are in House's office (or on the balcony) discussing Sherlock Holmes and his relationship with Watson. House remarks that Holmes and Watson were a couple by (he names the title of a book, but I don't remember).
Near the end of the fic, House says that Holmes and Watson didn't risk their lives and reputations just for sex (earlier, House had somewhat jokingly implied that it was just sex).
ETA: I found it. It's
Gumboots by
marginaliana