Also, can you imagine what going on a date with Mulder would be like? Or a vacation? What is his actual personality when separated from his work? There are a lot of jokes about Mulder jerkin' it, but that seems pretty reasonable, since he doesn't have any kind of social life outside of the X-Files. He has no interest in dating. In Season 8, when Scully is preparing to have a second child from medical rape at the hands of a shadowy organization, she says she "can't live like this, the subject of some unending X-file." But that's the only way Mulder wants to live.
This is the perfect example of writers using fundamental personality differences to create dramatic tension, and viewers then insisting that tension has to be sexual. You have to wonder how many fans thus grew up thinking that it's hot when couples constantly disagree. It's not! It's awful!