They're marked as soul mates (sorry Han, but for the sake of this fic.) They're also brother and sister. They don't really know what to do about it--how can they just walk away from each other? After finally FINDING each other after so long.
Possibly why Yoda and Obi-Wan separated them in the first place.
Luke/Leia, soul marks
Possibly why Yoda and Obi-Wan separated them in the first place.