Kylo copes with his demons by fucking, he lets the lowest rank officials and stormtroopers have their way with him in the most degrading ways and then just goes back to his quarters covered and full of cum.

Hux finds out and watches him, maybe just once or maybe several times and makes it a habit. You have free rein with regards to his reaction, maybe he is always disgusted, maybe he is smug, maybe he's turned on... anything works for me :)