
Just to see if I understood the plot, they were together in the past life and Ido treated him like shit so now he wants a redo?

That's not fully true. Idos brother sa him and then sejin came home after and didnt tell ido and ido thought he was cheating on him and then he got angry and sa’d him. Ido was in the wrong dont get me wrong im just correcting that he did that after he thought he was cheating and not just because (again he was still in the wrong and past ido was a toxic mess)

He was mean and rude but sejin was in love with him and willing before (at least thats what i gathered) but after the incident with his brother he realized ido didnt love him and if im not mistaken he got pregnant but lost the baby and that was his final straw. After that he killed himself and ido then realized he should have treated him better. Also the whole stealing the paperwork incident happened before as well but sejin wasnt honest with ido about it and that added to idos hatred towards sejin. Basically a ton of misunderstandings and miscommunication happened in their relationship, ido was a terrible husband and sejin was a pushover but didnt deserve what happened to him.
Suffer