Hi Zach,
How exciting to be planning your first trip to Walt Disney World! Let me offer you some thoughts on purchasing your
Walt Disney World tickets.
You will in fact need to buy a three-day park hopper ticket for both you and your fiancee. Each person does need his or her own ticket. You cannot use more than one day of a ticket per day - so if you had a six-day ticket, you can only use one of those days per day.
I suggest that you be sure to set up a
My Disney Experience account, and be sure that your tickets are linked to both you and your fiancee. Once your tickets are linked, you will be able to make
Disney FastPass+ selections, to experience some attractions with shortened wait times, before you even leave for your vacation!
I hope that these thoughts are helpful for you, Zach. Have a great time planning your magical vacation, and please do let us know if you have any further questions.