This was the question put to "Ask The Archivist" on the official Archie Comics website.
The short answer:
"How could he even have time? There's too much food to eat and too many naps to take!
His Wikipedia entry clarifies things further:
"Jughead usually doesn't like any long-term relationships, largely due to the observation that dating complicates a guy's life and deprives him of cash that could be used to buy burgers."
