
Can someone spoil me a bit here? Like, what's the endgame? Does Sejin regain his memories or is this a flashback only for the readers' benefit? And what happens to their relationship now? Just a teeny tiny spoiler, please.

Quite a few chapters is going to be their first life now. As you can tell, their relationship wasn't as good before. Sejin's family, mainly father is a very openly greedy and disgusting man, which Ido could clearly tell and knew that his father would probably want to keep tabs on the family through Sejin. (Which he did, although Sejin refused at times) So he kept Sejin at a distance, and Sejin's abnormal omega glands leading to uncontrollable heats didn’t help his situation. Obviously, Ido was also a big rude asshole, so he never tried to see whether Sejin was nice or not from the beginning and made his assumptions.
They actually slowly began to get closer and be cordial with one and other, until the Sejin getting information (USB) for his father is caught by Ido. Ido actually asks Sejin to explain himself, like given a reasonable excuse that he could maybe understand with, but Sejin kept quiet leading to them going back to square 1. Or worse.
During that time, Ido's older brother r*pes Sejin, and implying that Ido knows and sent him to R Sejin. This completely breaks him. Ido comes back and thinks Sejin and the brother had a consensual affair, and in anger R and bonds with him too. Where he feels all of Sejin's emotions, and leaves ashamed, but also to kill his brother.
Sejin then realises he's pregnant, but the thought of not knowing whose kid it was disgusted him so much he shot himself with Ido's gun. Ido after sometime then shoots himself too, after which they come to this life.
Here, Ido's plan is to not have Sejin to himself, but to get him away from his family and make him stand on his own. But he pushes him away, he still couldn't completely resist Sejin, leading to the kind of relationship they have now.
Sejin gaining all his memories, leaves him and focuses on his business. But they both miss each other, and they get back together.
I'm barely holding on hoping for the fucking script flipping haaa I'm dropping now bye