how do you feel about joint accounts

I would like to hear your views on wether you think its just for married couples our ok i general. Me and my fiancé have been together 5 years we share bills , planning our wedding etc I suggested we keep our separate accounts but also get a joint account to save money together but he said no because were not married , and i dont plan on getting married soon because of school so i dont understand the logic. Our premarital counselor suggested he show me hes stepping up financially and that this would be a good way so i can actually see hes saving money he agreed in the office but then he hits me with this.