Ik im the reader so I know things she won't, but come on, there's so many hints that should leave her questioning things.
1st. Her aversion to her husband. That's not something u ignore, especially since it keeps happening... Like you should be looking into why that is.
2nd. The call for misfortune, someone said they'd had fortune since the empress came and now all of a sudden there's misfortune... how about we take a step back and see what's changed. Oh look a new mistress.
3rd, the duke said he still loves his lover, but then says he wants to stay with you? I'd be questioning him so much.
Anyways lm gonna let this marinate, otherwise I might lose it. ( ´,_ゝ`)