It seemed like in "The Doctor Dances" the Doctor and Rose's relationship started becoming a bit more intense. (Romantically speaking, that is. Their friendship was already quite deep at this point, but Rose didn't have the Doctor in her "man" category and the Doctor wasn't taking the lead on anything.) Did Jack come along just at the right time to nudge (push/throw) the Doctor and Rose into more of a romantic relationship? Did they need a bit of shaking up at that point in order to shift from BFFs? Or was Jack not a factor at all and their relationship would have gone the romance route anyway?
Jack: Asexual, Doctor?
Doctor: I TOTALLY AM.
Rose: Whatever.