Tsukushitagari na Uchi no Yome ni Tsuite Deretemo Ii ka?

Synopsis

Riko Hanae, the most beautiful girl in school, proposes marriage to me, and before I know it, we're living together as newlyweds. But don't get carried away. This is a contract marriage. I asked her why she was so devoted to me. She puffed out her cheeks and said, "You're so naive, Minato-kun…" Wait… this is a contract marriage, right…? This is a love comedy that begins with a zero-day marriage that just goes on happy ever after. (Source: Shueisha, translated) Note: Includes 3 extra chapters.