Toumei Ningen ni Natta Watashi to, Watashi ni Kyoumi ga Nai (Hazu no) Otto no Kimyou na Sankagetsukan

Countess Aurelia has been living in silence with her husband, Leclerc, whom she married at the age of 18, for two years. She has adored him ever since she first saw his portrait, but she discovers that Leclerc has a former lover with whom he broke up due to opposition from those around them. Trouble...

Source: MyAnimeList