Falling Into the Deep End

It's love at first sight when Estella, princess of the kingdom, meets Isaac, the margrave's heir. She pines and pines after him only to learn that he's already engaged!

Devastated by the wedding, she hears a voice calling to her, when she suddenly falls into a pond and loses consciousness. She wakes to find out seven years have passed and she's... married to Isaac?! Now, she has a collapsing marriage, two children, and a host of strange decisions to unravel and figure out why she ended up here!

(Source: POCKET COMICS)

Note: First released in English, with the initial eligible release in Japanese followed by Korean, making it a manga by our standards.