Jiki Koushaku Fujin no Yakuwari Dake wo Motomete Kita, Koori no Bara to Utawareru Danna-sama ga Kateinai Stalker to Kashita Ken

Viola, the daughter of a declining count (she was Japanese in her previous life), was married off to Albert―the next duke―by her parents. However, on the very first night of their marriage, her husband declares, "All I ask of you is that you carry out your role as the wife of the duke in appearance only," effectively shattering any hope of a romantic relationship. Despite the soul-destroying statement from him, Viola picks up the pieces and starts to live happily and without restraints, announcing, "Forget my ice-cold, rude husband. I’m gonna live my life the way I want!" However, her new husband and mansion seem to hide a secret...?!

(Source: K Manga)