It's certainly something he's thought of before. With the Keyblade War nearing an end, he was going to have to talk to Ansem properly eventually. While they'd spoken briefly in Twilight Town, they had been more concerned with seeing the man safely home than with discussing their own history.

"I have already told him that I wish to atone for my misdeeds. I would also tell him that I am deeply sorry for the harm I brought to him. I cannot change the past, but I may yet be certain that I shall never again allow myself nor the fruits of my labor to be used against him."