I Married the Coldhearted Beastman Prince as a Substitute, and He Doted on Me as His Mate.

https://www.cmoa.jp/title/299982/ Milia, a maid devoted to her beloved princess, would do anything to protect her. When the princess is suddenly demanded in a political marriage by the neighboring beast-man kingdom, Milia is horrified—the groom is rumored to be none other than the infamous “womanizing prince,” known as the worst of the worst. Determined to shield her lady, Milia resolves to become the substitute bride herself. Fortunately, the prince seems to have no interest in his bride at all! Her plan is simple: quietly endure six months of marriage, then arrange a clean divorce. But things don’t go as expected… The supposedly cold prince begins to pursue her sweetly and insistently. Could it be that the cruel prince’s overwhelming affection is far too much for a mere stand-in bride to handle…!?