"Han har en kjæreste i Göteborg" is my suggestion, but I'm not fluent in Norwegian, so I'd rather leave this as a comment. Please let me know if this is right
I believe it is corect, but let me check with my husband today. He is the one who speaks Danish and Norwegian. The only thing that I ma not 100% sure us the spelling of "kjæreste". I believe it is "kæreste"...