The problem may be that 'novio' is male, while even in English, 'fiancée' is female. (We English speakers nicked 'fiancée' (female) and 'fiancé' (male) off the French. However, it's alright, we paid the French back by giving them 'le weekend'.)
Thats because fiancee is the femine spelling. Novio refers to a male and fiance comes from the french word where the noun also agrees with gender. So even in english the word is spelled fiance, when referring to a male.