Hey guys, so what i'm about to post, is a spoiler leading up to chapter 62, the latest chapter on lezhin. Anyhow, what i'm about to post isn't what happens on a chapter to chapter basis, but why there is a 2nd Jia, and why the father is so against the relationship/marriage of our Jia and our protagonist. Read at your own risk!! Firstly, there is no NTR in the CURRENT timeline, or rather the story we, the audience, are reading. The manga has time traveling, and thus different branches of futures as well. The time traveler in this manga, is the father of Jia. The one who is in the hospital, and the one who is very sporadic and angry all the time. He is against the MC and Jia's marriage/relationship for like the first 50 chapters so far. To start, I think you all already know from the first few chapters that the MC and Jia have been dating for over 10 years. The MC was Jia's High school tutor, and lover. They really do love each other, and from the very beginning of the manga, I think you all can get that feeling that perhaps the two aren't on the best terms lately. Mutually speaking, they both still love each other, but the MC is struggling to ejaculate apparently. Jia obviously is stressed out because of that, since she thinks that the MC is starting to lose interest in her. Furthermore, the father is so against their relationship, as shown in a flash back, and the MC mother is against Jia being in a relationship with her son as well. The mother is trying to get the MC together with that black hair girl. Oh and also, that black hair girl is one, if not the primary antagonist of the whole story. She's seriously crazy. Anyhow, what I want to spoil for you guys is that Jia's father has somehow been granted some ability to transfer his consciousness into the future, or perhaps its simply time travel in general, but nonetheless, everytime he does this, he ends up time traveling to the last moments of Jia's life. The father has seen her daughter die in different ways over and over, and he wants to prevent all of this from happening. In one time line, we find out that Jia dies from being hit by a truck after seeing the MC fucking the black hair girl in a car. In this future time line, there is no 2nd Jia, and the MC and Jia are married. They are struggling with there relationship though, because of similar reasons that were told in the beginning of the story. In this time line, the MC still can't ejaculate, and Jia continues to get stressed out. Furthermore, there families are against the relationship, and a lot of things are going on in their minds. One day the MC goes drinking, and the black hair girl appears to take him home. She obviously was stalking the MC or something, and when the MC gets in her car, she seduces him as he's drunk, and fucks him in the car. The MC tries to tell her to stop, but she uses the MC phone to call Jia without him knowing. When Jia appears, she sees them having sex in the car, and a truck hits her as she's still in shock. The father saw all of this, and when his consciousness goes back to the past/present, he believes that the MC is a cheater, and someone who can't possibly make Jia happy. That's why he's so against her dating him.