What just happened? I'm confused and can't follow Geon's thought process.

He thinks he cheated during his rut because of the omega pheromone perfume Hyundal used, and that, combined with his low self-esteem, has made his feelings of guint surge enormously and he feels like he doesn't deserve to be with Hyundal anymore.
It's infuriating to read, but I at least understand what's going on in his head