I believe I may have ... [He stops, not quite sure how to put it into words. These kinds of thoughts were a long time in coming to him, after sweeps of being alone, unchanging, never growing older, never becoming what he should have. Stasis in death had given him at least some perspective on what he had perhaps done wrong in their relationship, but it hadn't suddenly made him eloquent about such things.]

I wanted you to be a thing which perhaps you weren't. I mistook certain attributes of yours for your whole being, and thought all I had to do was fix the rest.

I believe now that you probably did not need fixing.

[He's grateful she's not looking up - it's hard to admit to such a wrong doing, different than confessing little peccadilloes in the hope of chastisement. This is a real thing he did, and the part of his old self hanging on is furious at him for apologizing to a lowblood for trying to better her station. But he suspects he never really made her happy, not in the way other trolls did, and for that he really is sorry. It makes him feel like a failure, and not in the pleasant, perverse way.]