Saikon Shounin wo Youkyuu Shimasu

Navier devoted her life to ruling the Eastern Empire beside her husband and childhood friend, Sovieshu. But when he falls for his concubine and demands a divorce, Navier shocks the empire with her response. She accepts and requests a remarriage to Heinrey, a prince of the Western Empire. Now, the fallen empress fights to seize back her future and turn the tables on those who cast her aside!

(Source: Crunchyroll)