Probably analyzing this way too much but here we go (also I never read the novel, this is just what I'm seeing so far). I think the Emperor probably does have some sort of feelings for Navier (might not be romantic, per se, but some form of love) but because she is such a "cold" person he feels like he's not getting anything from her. Basically he's like a spoiled kid who didn't get the candy he wanted. Because of that, he latches onto Rashta quickly since she depends on him and gives him the attention he wanted from Navier but never got. It's so frustrating to read his character because dude, obviously you don't deserve Navier's attention at all and why tf do you care who she's with all the time when you have a concubine. Still, I think deep down he really wants Navier to give him lots of attention and feels jealous whenever she pays attention to other people.
Probably analyzing this way too much but here we go (also I never read the novel, this is just what I'm seeing so far). I think the Emperor probably does have some sort of feelings for Navier (might not be romantic, per se, but some form of love) but because she is such a "cold" person he feels like he's not getting anything from her. Basically he's like a spoiled kid who didn't get the candy he wanted. Because of that, he latches onto Rashta quickly since she depends on him and gives him the attention he wanted from Navier but never got. It's so frustrating to read his character because dude, obviously you don't deserve Navier's attention at all and why tf do you care who she's with all the time when you have a concubine. Still, I think deep down he really wants Navier to give him lots of attention and feels jealous whenever she pays attention to other people.