Thinking deeper about it——even if Albedo didn't mind——what would his friend Tabula Smaragdina think if he knew what Ainz had done?
And how would he feel about this? To have the NPC he created rewritten by a friend...
He was taking advantage of that, using the fact that Albedo wouldn't betray him. He hated himself for this.
Ainz shook his head to get rid of his negative thoughts. All of his strong emotions became suppressed after he turned into an undead, but he could feel emotions of this level as if he was still a human. If his mind really became that of an undead, he wouldn't have to feel such a sense of guilt anymore.