I think the wedding at the end was just an imagination. Looking at the first parts of the first episode, she was imagining herself as the one being married instead of her friend. The setup of the wedding was the same together with their outfits. So, i think they did not have a wedding at the end. Instead of describing this drama as a happy ending, I think it is more appropriate to describe it as an open one. It is up to the audience to decide whether they end up together or not after the stairs scene at the near end of the last episode.
SPOILERS:Currently watching and on ep 9......I really liked it generally, it was entertaining and funny especially…
Yeah they did switch back cuz in their dialogue while walking at the park, min wanted a daughter but then was asked by petra what if min was the one giving birth next time is it ok for him?