My read on it was that he knew his mate was her but deliberately chose not to recognize her to be a perfectly rational ruler without human emotions and he assumed she would never leave him because she was in love with him.
I agree I agree I agree. And although it wasn’t really addressed the advisor he kills in an earlier chapter may have played a bigger role in their relationship dynamics beyond his role in having her accused of treason, like convincing him it would benefit him/the nation to keep her in that in-between status of never being recognized as his mate but kept on the shelf for him to use to prove his legitimacy as emperor. I’m also now wondering if his past action of ‘choosing’ a mate to ascend when he previously awakened also influenced how he treated Solan in their original timeline. Kinda like ‘I’ve done this before, don’t really need a legit mate just the figurehead of one, if I didn’t care for the fake why should I care for this one’ something along the lines of proving his control over her and the situation in general. Plus I REALLY wanna crawl around the inside of his head especially after she passed in their original timeline , not just to see his thoughts but to see the suffering ya know?
honestly if FL was a real person and had reached that point of no return, i don't think she would be able to love him again but i'm going to try to get invested since that was effing adorable. he's becoming human for her. i hope there's some lore as to why he didn't know about her or something though.