Ah so the earlier translation of the bride as Yuri's cousin was also technically right.
Also, as much as I love these stories, it would be great if the artist mixed up the colours a little... everyone looks the same.
I was totally ready to call Yuri out on his behaviour but then I realised that he's not just being an A-hole to a guy who's heartbroken, he's worried that his sister married someone who doesn't love her. So it's more understandable. Still feel sorry for Sunwoo though.