For you who lazy to scroll down to search for the answer.

Just like IslandGirlIslandLife wrote in the comment section. She describe this special ep very precisely. And I quote it: 'The first 5 mins is them one year later married and pregnant, then her water breaks. You get to see where all the couples are at and apparently all of them are bffs now. The families are all friends now, including the dad. The rest of the special is just right after the proposal where they are doing an interview style of a recap of their lives and how they got together. So it's just flashbacks. Then it ends with a weird dance number and you remember that Kido was in fact a C-idol.'

Yeah I kinda feel the drama kinda lost something for closing the curtain. But this special ep kinda help close the curtain for me..... but unfortunately they so far has no eng sub for this on YT. Here the link for you who still want to watch it. https://youtu.be/ucLmESbVLxc