
It would also be Ido's brother...yuck
Let's try work backwards:
"Whore yourself out" -> Sejin was still working at his father's company when the scandal broke out.
Previously, Sejin stole company information for his father, the scandal was in retaliation.
In the last season when Sejin confessed of nightmares of being raped, it was a slap in the face for Ido when he said "you're my first and only."
In the nightmare that one that violated him amongst "Have you slept with him" was "Knew... going to be like this", I think it's safe to say it was Ido because in ch 71, "I shouldn't have trusted you."
We can guess that Ido's grandfather also died around the same time? I don't remember if he dies before or after the scandal at Sejin's family's company.

Yes. Idos brother is what i meant to ask. So your saying Ido and his brother violated because I think I read a comment about Idos brother r***ping as well. Knowing that everyone of these pieces of shit and I do mean everyone in his past life didn't give a damn about I wish I could go into the story and beat the crap out of them all!!!
As I read the chapter of the past where Sejin meets Idos brother I have a horrible question that I just realized!!! In chapter 2-3 where sejin was having a nightmare of his past life being violated the shadow said 2 things " have you even slept with him yet" and " ill see you soon". My horrible question is could that shadow be Sejins adopted brother or Idos the way chapter was being portrayed?!!!!!!