The MC, Louise, is a reincarnator who has lived as a noblewoman for all of her second life and gets married to a Duke. Because of her past life, the thing she wishes for the most is a family of her own, though it has been a failure so far. She is empathic but not to the point of idiocy, and she tries to make the best of her situation with what she has. She is dignified but not overly arrogant about it. She is a romantic at heart since she always wished to experience love and have a family, but in the beginning of the story she accepts that some things have to be put aside. Sometimes it's frustrating to see what she has to deal with, like her husband's family, but it merely adds a cherry to the top because humans aren't just one-faced characters in a story book, and she truly gets back at those who made her and her husband suffer eventually. It's a gradual process though.

Because “Alec” and her husband are different, she does wonder sometimes (also her sister-in-law voices her suspicions) about the change and maybe her husband was like those novels where a suffering character dies, is reborn in another world, and comes back for revenge, but she dismisses it because

1) those are just novels, what were the chances?

2) if someone had really replaced her husband, why would they have stayed and even taken care of them with the bleak situation they had been in? A normal person would’ve abandoned them since they have no obligation towards them, after all.

This is why MC’s suspicions are not blaring during the build up of the story. But she’s intelligent and her realizations and reasoning really go nicely. It’s kind of a slow burn, after all. For both of them.

Contrary to my expectations, the husband is not an as*hole nor brutish to the MC, he's actually a good man and was kind-- too kind, in fact. Though he wasn't a bad man, he was very introverted and suffered from it (along with other stuff) which made him unable to function as a proper person, and even less as a husband and a Duke. Of course he wasn’t completely spineless or cowardly, but he really had too many factors stacked against him in this life. This might make the eventual switch (which happens in like the second chapter) troubling to know the more you read, but I implore you to give the novel a chance despite any aversion to NTR subjects.

The ML, "Alec", the guy who wakes up as the husband, is very down to earth and reacts as given of an overpowered protagonist who suddenly wakes up in another world.

He is a protagonist from a modern world where gates open and people start getting powers. They're merely mentioned as background building, so do not really expect to see monsters or everyday magic in this novel though, it's much more focused on the build up between Louise and "Alec". It’s a historical romance, though magic does exist in the world. He isn't super arrogant or brutish, and the way he thinks and makes the best of the situation truly demonstrates that in another story that this guy was the Protagonist of a novel with apocalyptic themes that saved the world instead of just a random overpowered guy. He is so charming and the way he's written is, idk how to say it, handsome? He’s considerate of the MC and initially tries to keep his distance from her, seeing it wrong of him to take advantage of her and the real Alec’s relationship to do anything, but he's too infatuated with her and eventually he falls in love with the MC. This story is as much the MC finally getting the romance and family she dreamed of as much as the ML falling for the MC.

This is my hypothesis of the novel. I've only reached chapter 87 and I have to wait for any more chapters to be released. Anyways;

There are extreme hints throughout the novel, even from earlier chapters, that the ML is actually the original husband of the MC. After he died, the husband is described to have wandered worlds, so logically he would've eventually arrived in modern Korea, becoming the protagonist of a Gate Apocalypse novel. However, he doesn’t recall any of this until waaaaaaaaaay later.

In fact, he spends most of the first half and more of the novel thinking he’s NTR’ing the original Alec lmao (he struggles with this and is full of self-reproach and guilt).

The ML - The Protagonist of another novel - saves the world and gets thrown into the life of "Alec Myers" as a literal reward for it, which confuses him and irks him in the beginning, because in the start he can't understand how replacing Alec is a reward in any way. His life s**ked, his dukedom was gone, he was broke, he was a figure of ridicule and torment, he even had to be the "Savior" of an empire after already having saved a world once, and he had no redeeming qualities except his handsome face and body. It's such a fraudalent employee contract and he can't even get a refund.

However, we eventually realize that it is because the System was fulfilling the wish he originally had, which was to become someone worthy of being Louise's husband, even if he had to die over and over again in his next life or the next and the next; also, as the Protagonist he had been forced to learn a lot of obscure and bizarre skills like horse riding and ballroom dancing and cooking and so on (otherwise he would get deadly penalties) which are supposedly skills meant to help him become a good husband for the MC.

The reward after the end of his novel is not for “the Protagonist of a Gate Apocalypse novel”, but it is the reward he sought ever since his first life as “Alec Myers”. Truly, it is a love and obsession that transcends time and space.