MC character in the first arc supposed to be an opportunist, lonely, distrustful, but gentle and cunning in the outside. It took her some time to consider the people around her were living breathing beings and not just characters she read. Even though near the end of the arc she seemed to be quite sincere to the family, she still held reservations and suspicions that all her connections with the siblings will be abandoned when they met the Original FL that could give more benefits in term of their careers than her. This showcase how much of a distrustful & lonely person she was.

But the second she met ML, MC characters break. The author wrote as if MC remembered everything that the original body experienced, even the time in her adopted parent house, but she conveniently just forgot her own husband face? And the part where the sisters just shoved ML & MC together into one room and MC suddenly didn't have any excuse to remove herself from the situation or a but hesitant about the sleeping arrangement? They're at best acquaintance at that point.
MC till this point survive with her wit, there's no way she couldn't remove herself from that situation and she was highly distrustful individual. She wouldn't sleep with a stranger of the opposite s*x in the same room. Period. This is character assassination. Purely plot armor to get the story going. And it's not enjoyable to read.
Rather than romance, they regard each other as convenient warm bodies. For ML, she happened to be his wife who has birthed his child. For MC, he happened to be a rich ML who happened to be her body's husband. And this wasn't even valid cause the ML can't change his name. The marriage was dissolved. Legally, they were not together. But the author kept packaging this purely physical encounters as romantic. There's nothing that I read that made me root them to be together. Especially after I read the first arc, which mainly highlights MC ideals and characters, that make me realize that if first arc MC was the one that facing ML, she would be drawing line between her & ML the moment she realize who ML was.
And ML, in my opinion, was just a misogynistic lustful lucky man. When the parents who abandoned and tormented his siblings, wife, and child came to their house, in the name of filial piety a.k.a saving his big misogynistic ego, he led these people in. To the home that MC brother gave to her. In other word, it's not even his f-ing house. And he didn't heed his son telling them that they tormented him, he didn't heed his siblings stories how hard they used to live under these people oppression, but the moment he heard his 'wife' got teased by his stepbrother, he got mad? Cause someone touch his woman? What a misogynistic pig. Disgusting.
The child supposed to be a highly intelligent child who starved for attention. And he got it from MC. He was always vying for her attention. And he was also one of the first character that MC genuinely care and appreciate. Their bond supposed to be deep. He even mentioned her as Mom in all his monologue in the first arc. But he met ML and suddenly he addressed MC by her name but he addressed ML, someone who he just met a few times, as his Dad, deferred to his words, and act condescending to his mother. Suddenly he became misogynistic the moment his father enter the equation. The apple doesn't fall far from the tree I guess.
In conclusion, author should change platform from jjwxc to smut website cause author clearly just want to write smut or lost interest in the plot in the second part. Author better write the story description as "no communication just copulation" with the amount of non-explicit smut scenes, misunderstanding, and general lack of serious communication between any of the characters.

both FL brothers have relationships with ML sisters. Her twins married the lil sister, and his big bro although not married his child has speculation that his mother is from liang sister. And that's make it complicated and not acceptable if you thought in current society