Jimmy McGill and Kim Wexler (Better Call Saul) -- Their marriage is a direct result of the worst fight they ever had after Jimmy violates Kim's trust for the sake of one of their schemes. The only reason they're doing it is so Kim can't be made to testify against Jimmy if he gets into trouble. The wedding is an admission that Jimmy will never do better.
Victor Frankenstein and Elizabeth Lavenza (Frankenstein) -- Both characters have always been keen on the arrangement, but the notion turns dreadful for Victor when his Monster vows "I will be with you on your wedding night" after Victor abandons their deal to make the monster a companion. Victor assumes the monster only intends to kill him though, not having a great knack for putting William, Clerval and ELIZABETH together.
The Ashen One and Anri of Astora (Dark Souls 3) -- Following Anri's quest line along with Yuria's will lead to Yuria announcing that the player will be joined in wedlock with Anri as part of the plan for the player to become the Lord of Hollows. She does not mention that the wedding consists of Anri being dead and the player needing to stab an ornamental sword through her face. The "wedding" is actually a ritual to absorb Anri's Dark Sigils. Although being undead like the player, she may also come back as the Elite Knight that appears in the Lord of Hollows cutscene, though no other characters in Dark Souls respawn like the player does otherwise.
Victor Frankenstein -- Frankenstein
Emperor Kuzco -- The Emperor's New Groove
Greg Heffley -- Diary of a Wimpy Kid