After scene
Mom: "Why did you return?"
Dad: "You told me to."
Mom: "Just because of that?"
Dad: "Do you need any more reasons?"
Mom: "Then you should have returned a long time ago! I've been telling you to come back for years and you haven't even shown your face for all that time and now you're here?! Do you really want to die by my hands?!"
Dad: "It would be an honour to die by your hands."
Mom: "Stop joking!"
Dad: "Does this look like a joke to you?"
Random convo
Mom: *insert a colorful curse*
Dad: "Why are you so foul-mouthed? The child would be shocked if she hears this."
Mom: "I'm from a commoner background, I grew up on the streets, I never learned anything. Happy?"
Dad: "Even if you've never learned anything, you're better than those who have. It's fine."
Mom: "Ha, really..."
Even though he hated him so much he wanted to beat him to death, when he treat him like this, he would become weak-hearted. The time they'd spent together was too long to turn away easily.
Some q&a and someone ask the author for Valer and MC's reactions if Mehen ever get a lover.
Author said she can't picture it like...really can't but she'll try her hardest and use all her imagination.
MC would go wary cat mode "why is mom leaving me for a new mom?" She'd gradually become closer to the lover when she sees Mehen being happy. She'll probably like the lover for the traits that made Mehen like the lover too.
Valer would go, "wow...honey how could you cheat on me?" And he'd get smacked. He'll probably sincerely congratulate them but author thinks he'll get jealous that someone more important(?) than him has appeared.
Valer suffers from after-effect? and talks to Arelyn
"No matter what choice I make, no matter what I do, I always lose you."
"Why?"
"I don't know."
Valer gave a hazy smile.
"Sometimes I kill you. Because you look in pain, or I just go mad. And then Mehen leaves."
If Mehen left, he would become a monster. Her dad whispered such thing to her, as if telling a very old secret.
"He is the last shred of humanity I have left."
The only existence that ensures he never forgets he is human at any moment. The one person who never changes in any situation. That is why he is the only human Valer trusts.
"He was that kind of person."
Her dad laughed, saying the only one who makes the same, unwavering decision in any situation or moment is just him.
Valer declares his intention to not get married
Mehen watched Arelyn, who was constantly exclaiming in admiration while looking up at the sky outside, through the window, and a faint smile crossed his lips.
"I didn't know you could smile like that."
At Valer's voice, Mehen's expression immediately turned cold.
"Has your physical condition improved now, my lord?"
"Just enough to endure."
"Your after-effects are lasting a long time."
"Indeed."
"Arel said that you were saying strange things."
"Ah, that."
Valer closed his eyes.
"I had a dream."
"A dream?"
There was no reply. Mehen sighed.
"My lord, don't we have a conversation we haven't finished yet?"
"About us getting married?"
"You want me to kill you?"
"I'm scared, honey."
"Do you really want to be sued for harassment?"
Mehen got angry. Valer chuckled softly.
"Is there anything you want? I'll grant it."
"Sincere child-rearing."
"Rejected."
"Sincere performance of public duties."
"Hahaha. Rejected."
"Permission for my retirement."
"....Rejected."
Mehen threw a fountain pen. Valer, who expertly dodged it, clicked his tongue softly.
"Why do you only wish for things that can't be granted?"
"I have no other wish but that."
"Like money?"
"I have enough."
"Or power?"
"Not interested?"
"Or a woman?"
"......?"
"Are you not going to get married?"
Mehen's expression crumpled. Valer laughed at his never-before-considered attitude.
"You must start a family. Ordinarily and peacefully, like others."
"Me?"
"I can give you my title if you want."
"I don't need it."
"You're cold-hearted."
"Then, my lord, are you not going to marry?"
Valer tilted his head.
"Me? With whom?"
"Anyone."
"You know, Mehen."
The heated, magnetic eyes reflected Mehen. The dry declaration that followed.
"The day I become a family with someone will never happen again."
"Halbern ends with my generation, or with Arelyn's."
Mehen's shoulders stiffened for no reason upon hearing that.
"Who knows, maybe somedays you will fall in love."
"Love, huh."
Valer smiled. No emotion was reflected in his dry smile.
"Mehen."
"What?"
"Do I look like a person who can... love someone?"
His long eyelashes slowly blinked.
"Aren't you already in love?"
Mehen looked towards the window. Outside, Arelyn was still admiring the Sky Tower.
"That's not love."
"Then what is it?", Mehen retorted, "Cherishing and treasuring something, and guarding it with everything you have so as not to lose it..."
"Then answer me."
Valer gave a wry laugh and ran a hand through his hair. The magnetic pupils sank coldly.
"Is what I'm trying not to lose... the last tie to the sister I lost, or is it my daughter Arelyn?"
A provocative and blatant question.
Mehen paused.
"See, even you don't know."
"......"
And Valer got scared of his dream, worried that some days, Mehen would leave him for good. Valer really wants to burn the world to trash now lol.
The silence returned with a truly cruel grumble. A familiar and comfortable silence. The two were immersed in a sense of nostalgia, as if they had briefly returned to their younger days.
Dad: "Mehen."
Mom: "What."
Dad: "Thank you."
Resting his cheek on Mehen's shoulder, Valer looked at Arelyn outside the window.
My cute and lovely daughter. He thought.
Dad: "If you weren't here, there would be no Halbern either."
Mom: "......"
Dad: "Because I would have burned everything and buried myself."
It had been a long time since Valer, who had to endure such a strong after-effects by using power, looked this weak.
Mehen simply let Valer lean on him and do as he pleased.
Dad: "You won't leave me, will you?" His hoarse voice was particularly sorrowful today, "you won't abandon me, will you?"
Mom: "I will abandon you."
"Cold-hearted," Valer lightly laughed as he brushed his hair back, "but that's why I like you."
Mom: "......"
Dad: "Because you'll abandon me and leave without hesitation anytime I disappoint you."
Mehen suppressed the feeling of becoming serious, listening to the voice that kept whispering, to help him remain human in that way.
Mom: "Ah, I miss my sister......"
This hateful bastard. He won't even let me hate him.

Here's the scene and some spoilers that I've read
Dad: "All of a sudden, "mom"? You became a mother before I knew it. Time really flies, who would've thought Mehen would become a mother."
Mom: "If you want to die, keep talking."
Dad: "That's a blatant assassination warning how thrilling."
Mom: "What makes you think it'll be an assassination?"
Dad: "Then you're going to kill me fair and square? That's refreshing in its own way."
Mom: "Stop talking nonsense."
Dad: "Who's the child's father? Is it me? So you're my wife, Mehen?"
Mom: "Do you want to die?"
Dad: *laugh* "What's wrong, honey (he used 'yeobo' here)? It has been so long since you've seen this husband, I'm hurt."
Mom: "Shut up, please."
Dad: "But when did we get married?"
Mom: "Shut up."
And as I read more about some dialogue spoilers it seems that "honey" is a regular nickname after wife