Well Fuccboi was threatened some more but his parents and then they tried to make it look like Eunseo was cheating on Jinha (even asking their classmates and since there were already rumors and misconceptions, so many people thought they were dating, just to try and convince the grandfather). He went to her house and hugged her to make Jinha jealous (after spreading rumours everywhere) when he came in but instead Jinha punched him and Eunseo made it known that she hated him.
Fuccboi left and felt bad so he tried to commit suicide by driving into a truck, he survived but was in a coma. The parents raised he'll at the hospital even though they don't care about him but by then everyone thought Fuccboi was the other man. Gramps throws them out and disowns them but starts asking Eunseo to divorce Jinha (He realized how stupid his plan was and didn't want her to suffer anymore I guess). She does so after sometime and Jinha begs her to stay but she says some hurtful words for him to agree.
5 years later, she's a translator in the US, and goes back because she heard Gramps was sick. She meets Jinha after the visit and he asks her to teach him Russian because they have a startup in Russian she agrees and gets jealous of some girl she saw with Jinha who was his secretary that was telling people that Eunseo was back to seduce Jinha.
Older brother tells her that Jinha is lying, the company has been doing well for a while and he's only learning to be with her and that Gramps wasn't sick and that it was Jinha who asked him to pretend to be sick. She confronts him and he tells her what's up (that he still loves her blah blah blah )they confront the secretary who was a stalker and then she gets mad as because the stalking could have been avoided if Jinha didn't encourage her, he tells her he had to collect evidence. Anyhow she's still giving him lessons, she told him she loved him in Russian and then he kissed her and told her he never believed they were divorced and that he was just giving her space (which is...weird). She questions this but nothing ever really came of it.
They remarry like 4 years later (I'm not too sure) in Russia and take over the Russian part of the company. The end