Tsundere Detective Agency

From INKR Comics:
Cha Woomin is a private investigator whose specialty is to catch people cheating on their spouses. A rich husband hires Woomin to spy on his wife due to his suspicions of her being unfaithful. But as Woomin spies on this woman, he falls for her and learns the true side of her husband.

Original Webtoon:
R19: Toomics, Ridibooks, Lezhin, MrBlue, Naver Series, Anytoon, Qtoon, MeToon
R15: Ridibooks

Official Translations:
R19: English, Japanese
R15: Japanese