There's 3 more chapters of the side ship (including one 'long' chapter), then we get a series of chapters focusing on Naoto, before ending with some chapters about Mizuki and Kazu-kun again.
Note to readers, the next several chapters all focus on side couple(s); it'll be a while before the focus shifts back to Mizuki and Kazuya (though the volume ends with those two).
@Purplelibraryguy it is weird, but the Chinese scan literally transliterated "nii-chan" ([ou] ni jiang). (This isn't the first time it's done such things.) I have 0 clue what the Korean original said.
There are 74 chapters total across 3 volumes (I can't edit the page to reflect this, if anyone with privileges wants to do that).
Volume 2 goes up through chapter 49.