It's kind of funny in retrospect that he thought figuring out a way to get shielded from Nightmare would help. Nightmare knows him by now, probably knows him better than anyone else. It doesn't matter that he got someone else's shielding without them knowing that he did, because Nightmare does not need any access to his mind anymore to have a real fucking good guess of how to get to him.
"I thought I'd—feel worse. Or something. More conflicted. And I was feeling pretty bad at first, but..."
"I don't. So I, I wanted to figure out... if there was something I should be feeling and I'm not, or if I'm just pretending to myself and it'll blow up later, or..."
"...I don't know. I guess... I hoped it was going to become obvious or. Something. When I saw you."
"...okay, let's try to work through it, then. What do you think you—no, what did you think you would've been feeling?"
"...a bit. I, I talked to prez about it. About where the cuffs came from. It's so fucking stupid. Why couldn't we have found that dungeon six years ago?"
"...not right after. Maybe eventually. It just—it—no matter how I think about it, the backlash was making it worse but he wasn't backlashed when he was with me. He wasn't backlashed when he—apparently—lied about being able to shield himself from Nightmare.
"And, and whenever I thought about this, I kept going back to that. Why? Why did he do that? I liked him so much, Woo-young. I loved him with everything I had. I wasn't going to leave him, I never even thought about it, I, I kept having these silly dreams of, of us going to the West somewhere and getting married there. And we worked so well together, we—fit—"
Past tense, all of that. And Tae-gun isn't... freaking out. The way he did last time they talked about this.
"He ruined it. He ruined it. He ruined us. There, there were things we could've done better—could've kept him away from dungeons until he learned how to reliably not use his power on innocent people, could've invented better ways to make sure he was okay and guided and treated than just relying on his self-control, could've gotten him his own friends, his own life outside me—" All things Tae-gun thought of over the years, but didn't at the time. Things that occurred to him, and that he immediately forgot about because thinking about them was too painful. Things he... can think about, again. "But it's not my fault, Woo-young. It's not. There wasn't anything I—should have done better. Could've, yes, but... it shouldn't have needed it. I shouldn't have needed to be heroic about it. I shouldn't have needed to, to, to figure stuff out for the first time on my own as a twenty-one-year-old kid. I shouldn't have needed to find the right answer to not get abused.
"He could just have made good choices instead of bad ones."
"It's true! He could've trusted me! He could've asked! He could've talked to someone else, he could've—not made bad choices. It wasn't just one of them. It was choosing to do that over and over and over again, to keep doing it. He kept choosing it. And it's not my fault.
"And so I'm sad but... now that he's in prison, I'm..."