
I like the MC but I just really dislike the ML. I know he has "traumatic past" and has PTSD but still...
---spoilers---
He didn't deserve neither of the sisters. And his relationship with Rosemond and the things he did for her and let her get away with was irredeemable. Even after he switched his feelings to the Queen, if anything it just made him seem fickle. He was just as guilty as Rosemond in the past life too.
He also schemed with Rosemond against the queen (as part of the queen selection process which he let her take charge of) in this life too early on in the story.
It's only when she almost starts a war due to her childish pettiness by switching the meat during the banquet, he starts to get doubts (even that wasnt enough?).
And when she hires assassins to kill the queen, which almost kills him HE STILL pleads with the queen to let the bitch live. Despite, knowing what she has done and the threat she bares to the MC. All because he is "attached" to her.
Even if he had been "manipulated", Rosemond's power/influence only stretched as far as he allowed. Otherwise, she would of only been a nobody with lowly origins.
Atleast, Rosemond was like "yeah I was faking the love thing the whole time to manipulate you" when he lost interest in her lol.
And even she was like to FL "How can you seriously love that guy?" before she gets executed.
He is just so weak and needy. I like to think the FL ending up with him served more as a good for the well being of the empire rather "romance". Since, she is an excellent queen.

Was the ultimate bootlicker, even when backstabbed and betrayed the fool instructed his daughter to be subservient and loyal to the same Monarch who framed their family and his daughter. The King did this all just so in order to marry another princess in the MC's place. Her dad's "advice" basically was to proudly take her unjustified death sentence like a champ with no resistance. How meaningless.
Is such a weak man. No matter what we think of Rosemond, she is evil and vindictive - yes. BUT...all of her actions and schemes came with full backing and support from the Emperor who was "attached" to her. She wouldn't have been able to do none of the shit she did if it weren't for him protecting and supporting her.
Her power and influence stretched as far as he allowed - which was pretty far.
He killed innocents (including the FL) all in her name and a war was nearly started because her if it hadn't been for the FL outsmarting her.
He allowed that spiteful, greedy and evil woman to wrap him around her finger.
As sovereign he is culpable.
---spoilers---
The Emperor basically let Rosemond choose his "queen" and together they planned to eventually get the queen dethroned so Rosemond while she is rising up the ranks will take her place. Rosemond thinks (although its later revealed a lie by the doctor) that the FL is "infertile" that is why she selected her and the King knows this.
So when he made that promise to agree that only her child will inherit the throne, he agreed - since he thinks she is infertile therefore promise is worthless. But doesnt reveal this to the FL.
When the Emperor loses interest in Rosemond and ignores her, she schemes a way to make herself the official royal concubine by revealing that the Queen is "infertile" by demanding that the nobles have the FL do a fertility screen. Which is very humiliating for any woman to be subjected to let alone an Empress.
Rosemond keeps spreading these rumours and riles up the nobles to put pressure for a fertility screening until the Empress confronts the Emperor about why Rosemond is doing this.
When she confronts him he doesn't know what to say and she eventually guesses why Rosemond has as much confidence in her claims as she does.
And the FL also realises at the time of their "promise" regarding succession the Emperor was aware of her supposed infertility so he was basically mocking her to her face.
Now, the FL is in despair (like literally she is screaming at him "how could you do this to me?")
it's a very heartbreaking scene to read. That even the Emperor realises he really fucked up because at this point he is now in "love" with the FL.
The FL believes now he and rosemond have robbed her of a chance to live a normal life modestly due to their scheming, so she has to bare the public humiliation and shame of being an "infertile" queen like the previous queen did who eventually went mad -(ironically the source of the ML's trauma). The FL also says she was a fool to ever have shown sympathy or pity him.
I am mentioning this spoiler, because it proves that the ML didn't just do evil shit for the sake of Rosemond in the previous life.