Plane ticket times?
When you are purchase an airline ticket at the very beginning of the process, it will ask you have many passengers. You select 2, if it's for you and your future spouse. - Then when you are looking at the flight detail, where ever you are buying it from will know that it's for 2 people.
Ummmmm yeah. Every single website will ask on the front page how many travelers are in the group. The default will always be one in which you yourself have to change to 2 travelers. If you still cant figure out how to change the 1 to 2 travelers, than you either need to let your fiance book the tickets or go to a travel agency to book it for you. This is pretty basic stuff.
Of course you won't need to go on separate planes. Go right back to the beginning and make sure you've selected '2' on the 'how many passengers?' bit BEFORE you start on destinations and dates and so on.
Usually theres a preference to check at the beginning that says adults and you select 2 thats how its always been when ive used those sites which btw have ripped me off and stolen my money many times, be very careful
Just don't go