I'm really sorry but I can't find it again. I read it a long time ago and there are so many chapters that finding it again is not that easy (chapters don't have names, only numbers).
But if you want, I can give you some more context below.
(Big spoilers incoming)
Maxi will take part in the war against the monsters, breaking her promise to Riftan that asked her to stay in a safe place after the campaign we're seeing now in the manwha.
During the war, we discover that the monsters surprisingly have some sense of intelligence : Riftan and his stronger men will leave the rear units in order to fight the monsters but turns out that it was a trap made by the monsters.
In reality, they're aiming for the rear units now defenseless and where Maxi is.
On her way to escape in the mountains, Maxi thinks she can help the rear units from afar and try something that will be successful but at a heavy cost.
Maxi will barely escape death, being in a coma for a very long time after loosing a lot of blood, mana and something even more important she didn't know she was carrying : a baby.
Riftan will be completely destroyed by that and believes that since she ever became his wife, she only ended in misery and nothing will change in the future. He will then take his distances with Maxi without giving her any explanations of course because he's our miscommunication champion.
Maxi will believe that Riftan threw her away as she miscarried and has nowhere to go. However the duke, who perceive this miscarriage as a humiliation, wants to take her back so nobody sees her again.
Maxi knows what awaits her in the duke's castle but she's still very ill, weak, has nowhere to go (so she thinks) and is craving for a kind of punishment as she blames herself for what happened to her baby. She will accept to go back to her father's place without saying a word to anyone.
Riftan is convinced that it's the best place for her to be, as she certainly is living lavishly like a princess and recovering well surrounded by her family. He will be denied entering the duke's castle and he jumps to the conclusion that Maxi doesn't even want to see his face anymore. He insists tho, as he only wants to see her recovered state one last time before leaving and never coming back to her ever.
He gets to enter from a back door and discover Maxi, half naked, in a even worse state than she was in the rear units, bleeding from the whipping her father has been giving in what can possibly be a punishment room.
Shocked by realizing that all of his fantasies were false and that Maxi was accepting her fate without a word, he'll turn into a rage and beat the duke repeatedly until he sees him dead. Riftan's knights will stop him as he's not a noble and killing a duke is heavily punished but Riftan's punches are so strong that even if he escaped death, the duke will be left permanently disabled and traumatized.
From then on, Riftan takes Maxi back, they have a big conversation (that helps but still doesn't settle everything) and a trial will take place which will lead to the second main part of this incredible story.
I believe I've said more than enough ! I'm looking forward seeing all of this drawn by this amazing artist :)
btw, will riftan ever find out about how Maxi was treated back home? I don’t remember if they ever spoke about the miscommunication from before their marriage