? The crown prince and empress are kinda helping??

They’re both assuming Olivia still loves the guy and is doing this out of petty jealousy but it’s actually working out in everyone’s favor? The crown prince’s side chick is gonna get the authority of the crown princess to-be, and so will her family. Olivia gets to be with the duke, even if they push her to move out (which they can only really do by threatening her reputation but it’s already bad + everyone knows they’re promised to be married. Grace period or not). And Olivia’s sister now doesn’t have to get involved with the Crown Prince even while the imperial family assumes their loyalty is at the same level without that leash, so in the future her sister (and maybe the brothers) will have a chance to go against all of that to help her in the future