Perhaps in Luke's Jedi Order a Jedi doesn't necessarily have to dedicate their entire life to the order. Say if a Jedi falls in love or simply wants to retire then he/she can lay down their saber and they're free to live their life the way they see fit. That way they have no conflicting loyalties while they are a part of the order but also they aren't ostracized if they decide to step away. Perhaps this is the way Leia chose. She was trained to be a Jedi but instead of following that path like her brother she laid down her saber to be with Han and have a family.