What happened in chapter 17? I have not properly read and just skipped to it as I was curi...

So from what I've gathered all scenes that his hair is down and looking more innocent are from the past. His late husband's son was a client as we saw in chapter 17, and how he either convinced the son or managed to get in touch with his father is unknow. But it's pretty clear the son still treats him like a whore because he used him as a sex toy and even rubbed one off using his face when he first shows up.
We don't know if the old man that married Yuta was actually in love or into him enough to leave the state and his position in the company to Yuta nor do I know if they will show that.
The old men that are watching them are not the same from the golden pavilion, they are other heads from the same business branch Yuta's late husband was. They know Yuta's past and as he said, they hate the fact that a whore is "one of them". So they ordered them to have sex simply to humiliate Yuta because it's all they actually do. As he says they can't do shit, so they do that to feel good about themselves like a little revenge.
Yuta seems to have some serious issues from the Golden Pavilion and I'm 100% sure he is in love with the ML since their first meeting and he resents and denies that with all of his being. He hated thinking about calling him for help, he hated that he thought about him, he hated that the ML was nice and gentle, he wants to believe that all he was is a hypocrite who showed him fake compassion and doesn't actually care. We are yet to see more about their relationship from the past because it seems in the first chapter that the ML actually had nothing against Yuta and even seemed glad to chat, until he showed his true intentions and drugged the ML.