My Happy Marriage (Japanese: わたしの幸せな結婚, Hepburn: Watashi no Shiawase na Kekkon) is a Japanese light novel series written by Akumi Agitogi [ja] and illustrated by Tsukiho Tsukioka. Initially published online via the user-generated novel publishing website Shōsetsuka ni Narō, it was later acquired by Fujimi Shobo, who has released the series since January 2019 under their Fujimi L Bunko imprint.

A manga adaptation illustrated by Rito Kohsaka [ja] has been serialized in Square Enix's Gangan Online service since December 2018. A live-action film adaptation premiered in Japan in March 2023. An anime television series produced by Kinema Citrus aired from July to September 2023. A second season aired from January to April 2025. A new anime project has been announced.

In an alternative version of the Taishō era in which spirits and magic are real, but in decline, Miyo Saimori, born without supernatural talent, is forced into an existence of servitude by her abusive stepmother. When Miyo finally comes of marriageable age, though, her hopes of being whisked away to a better life crumble after she discovers her fiancé is Kiyoka Kudou, a commander apparently so cold and cruel that his previous would-be brides all fled within three days of their engagements. With no home to return to, Miyo resigns herself to her fate—and soon finds that her pale and handsome husband-to-be is anything but the monster she expected. As they slowly open their hearts to each other, both realize the other may be their chance at finding true love and happiness.

Written by Akumi Agitogi [ja], My Happy Marriage began publication online via the user-generated novel publishing website Shōsetsuka ni Narō. The series was later acquired by Fujimi Shobo, who began publishing the novels with illustrations by Tsukiho Tsukioka on January 15, 2019, under their Fujimi L Bunko imprint. As of March 2026, ten volumes have been released. To advertise the fourth volume of the novel, three promotional videos were released on September 15, 2020, featuring the voices of Kaito Ishikawa, Reina Ueda, and Yuki Yagi as Kiyoka, Miyo and Kaya, respectively. In June 2021, Yen Press announced that it licensed the novels for English publication.

A manga adaptation illustrated by Rito Kohsaka [ja] began serialization online via Square Enix's Gangan Online service on December 20, 2018. As of March 2026, six tankōbon volumes have been released. In July 2021, Square Enix Manga & Books licensed the manga for an English print and digital release. Square Enix published an art book on August 10, 2023.

A live-action film adaptation was announced on April 25, 2022. It is directed by Ayuko Tsukahara, with the screenplay written by Tomoe Kanno [ja], and music composed by Akiyuki Tateyama [ja]. The film was released in Japan on March 17, 2023, by Toho. Idol group Snow Man performed the theme song titled "Tapestry" (タペストリー).

The film had its North American premiere at the Toronto Japanese Film Festival on June 10, 2023, under the title As Long as We Both Shall Live. It was also screened at the Fantasia International Film Festival on August 8 the same year.

An anime adaptation was announced on April 5, 2022. It was later revealed to be a television series produced by Kinema Citrus and directed by Takehiro Kubota, with supervision and storyboards handled by Takao Abo, scripts written by Ami Satō, Takahito Ōnishi and Momoka Toyoda, character designs by Shōko Yasuda [ja], and music composed by Evan Call. The series aired in Japan from July 5 to September 20, 2023, on Tokyo MX and other networks, with Netflix simulcasting the series globally, while Bilibili simulcasted it in mainland China. The opening theme song is "Anata no Soba ni" (貴方の側に。; lit. 'By Your Side') by Riria [ja], while the ending theme song is "Vita Philosophica" (ヰタ・フィロソフィカ) by Kashitarō Itō [ja]. The thirteenth episode was bundled as an original video animation (OVA) with the special edition of the eighth light novel volume, which was released on March 15, 2024. The OVA premiered on Netflix on November 22 of the same year.