Perhaps the reason Luke is on this self-imposed exile of his during the sequel trilogy is that he was responsible for the death and destruction shown in Rey's vision in The Force Awakens.
Han says something along the lines of 'one student fell to the darkside and ruined everything', but maybe Luke flips out in a moment of emotion and is the cause of the vision itself.
It could be that he was on the defense of something or just had enough of some students not obeying the rigid tenants of the Jedi ideals / messing with the darkside.
As we know from previous films, the line for crossing to the dark side can have "good" intentions and is a slippery slope that gradually gets more and more out of control.
It's very possible that his failure as a teacher or his use of anger in fighting led him down the path to the dark side.
Perhaps after the fight, he regrets his actions of acting out on his emotions and realizes that the power of the force is 'much bigger' than light vs dark.
Rey would be sent to Jakku to keep her away from Luke...
so Rey was already known to the core characters which would explain their reactions to her ( Han's guilty look at Rey's that much green comment, and the hug from Leia.)
Not a ton of evidence either way and it's a bit of a long shot, but it's an idea!