Your fiancee should be able to still come visit there for up to 12 weeks each year just under the normal visa waiver programme, same as any visitors. Your visa will be a sticker on a page in your passport. But this wont show in your fiancees passport.
My own g/f lives in Orlando and I am in...
My American girlfriend has a marriage settlement visa approved to come live with me in the UK. It expires in early July and due to work commitments etc...she will likely come over and we'll marry at the last minute.
However a month back she was arrested at an airport over an unemployment claim...