Then, the plot of poisoning Juer (MC's brother) happens.
Is quite long, I will only say that Ouyang Nuan was a little too dense to not realize immediately that everythings was Xiao Tianyi's schemme in order to force her to leave with him.
At the most crucial moment, she pretends to kill herself with poison, not after telling Tianyi (and Zhonghua is also there), that she loved him in the past but can't reciprocate since his ways of forcing her, she doesn't like those. And that she realized she didn't want to leave her husband.
During that plot, Juer's bethroted's family try to cancel the marriage. It is Chu Wangfei, but in the end,they get married & Juer is also cured.
EDIT: (I misunderstood something)
Then, a princess and a prince from a neighbourg country and a besuty from Tianyi's country (the one he became Emperor of) are sent to the Crown Prince's manor (Xiao Yan) with the purpose to make peace.
Meanwhile, MC deals with both of the step-mother-in-laws, Dong Hao, maids, so she suffers a loss & als gets confined for a little while.
She seems to team up with Prince Yan (Crown Prince) & Tianyi to attempt to stuff the Princess from that country as a concubine for ML. Although they first try with the other beauty (Yan something).
ML refuses (first that Yan girl, after Xiao Yan switches to the Princess, the other), MC refuses saying it is not healthy to have so many women & her husband has injuries ( implying he has some sort of disease) and they anger Xiao Yan and other elders.
The thing is, MC is more ruthless now, but at the same time it seems she lacks some sharpness to anticipate certain schemmes.
The villains don't go easily away, either. Perhaps, there are too many of them.
Also, during this arch, as a resulto of Tianyi's schemmes (poisoning Juer & sendind that beauty for Zhonghua), MC & ML kept opening their hearts and mind to each other.
ML has been more concrete at expressing his feelings (saying literally that he loves her), and has told her he fell in love a long time ago and was determined to get her, but that he also tried to be cold & distant with her to not reveal his heart.
MC has started to acknowledge she's developed feelings for him, and is no longer resigned to the possiblity of him having concubines (even though she told the Crown Prince she wanted to be the only wife), she starts showing more possessiveness and some sweet & funny moments also happen between the couple.
By the way, The couple of brother & sister from Tianyi's country end up in MC's & ML's house anyway.
The step-mother seems to be on the schemme, as she asks her to accompany her to the temple and, in the way back, a fire happens at the Crown Prince's house (they're passing by), and they stop to try to save that Princess but, in the end, is her whom takes an arrow directed at MC.So they take them both home.
And now, Dong Hao has some other schemme in her hands that probably goes beyond the attempt of stuffing the princess as Zhonghua's concubine.