The author is boxed a bit into a corner with the storyline because the husband, Roxy and the maid are so unpleasant but they are also so much in control of everything. Unless there are some clever plot twists, I think we might end up being disappointed. It's definitely great writing and I don't think I've disliked characters so much since The Remarried Empress.
Because Mr sneaky threatened to have him killed and both Lords know he's an assassin. It'll be in the assassin's favour to get rid of Mr sneaky or make Seungho catch him in the act.