@Sarsak: In the novel, Sovieshu (emperor, soon to be ex) is overall a fairly decent guy... for being an emperor who thinks nothing of getting a concubine while being married. Like there are some outrageous bastards in some of these novels/webtoons, some borderline or outright domestic abusers, and this guy is so not on their level. He's very pedestrian entitled douche.
@Krobelus: The reason for why Sovieshu and Navier's marriage is falling apart is easy to see in the novel (we're up to ch80+ and getting ever closer to their divorce in real time), and while it's not explicitly stated, if you pay attention you can definitely see how Rashta is a catalyst that exposes and deepens already present fissures in their relationship.
Also, there's definitely magic in this universe. It's not very present or obvious in the beginning, but this is definitely a fantasy universe that deserves a fantasy tag.