Kekkon Yosou yo(1996)

Kekkon Yosou yo

Mitsuha and Kota have been good friends since high school and are currently living together! However, they are not dating as potential marriage partners, but rather, Kota moved into Mieha's apartment and they are just casual roommates. Neither of them has much desire to get married, and both want to live happily in the moment. Although they are kindred spirits, they hope to find their ideal partner someday. However, it is always their friends and acquaintances around them who are finding happiness. They are always getting invited to weddings and having to congratulate other people as guests... Will they ever find a happy "marriage" of their own?

(Source: Office Manga, translated)