Fukushuu wa Mitsu yori Amai

As the empress, Alexandra should be the most respected woman in the empire. She did everything she could, even sacrificing her own parents to make her husband the emperor. But instead of showering her with gratitude and love, Kleio repays her by framing her and sentencing her to death. So in the split second before her unfair demise, Alexandra offers up a prayer to God. Next thing she knows, she's opening her eyes six years in the past on the day she married Kleio. Alexandra's prayer has been answered, and now... it's time for revenge.

(Source: Tappytoon)