Before the 'revelation' that Leia was his sister- I think this, Boost, is a critical reason why Luke ends up on the 3rd side of the Han-Leia-Luke love triangle. Sure, Han and Leia had great love/hate chemistry, but Luke and Leia were both leaders. She was a political leader/ruler on Alderaan and then again in the Rebellion. Luke was a war hero, a powerful Jedi, and a true believer in the Rebellion. But he was also 'unavailable'. His destiny (through the end of RotJ, at the least) was all-consuming and left him unavailable for much of a private life. On the other Han, (see what I did there?) Han was sort of a "nobody" with a fast car and hot hands. He was much more available and that can trump everything else.

After RotJ, especially if Luke decides to run some sort of Academy for most of his life, I think he'd definitely want and have the oportunity to settle down. And, if she's capable, they can go off on adventures together. The part of Survivor's Quest that I liked and can remember was just that: a Mr. and Mrs. Skywalker Mystery Adventure.