The fact that you are not living together will be an impediment to obtaining approval but it is not impossible. The test is whether your marriage is bona fide at its inception, i.e. at the time you got married did you intend to spend the rest of your life together? The fact that you are or are not living together is only one issue that is looked at. You and your fiance will be best served by consulting with a very experienced immigration lawyer who has handled cases such as this before. This is not the type of case you should be handling on your own.