Hate to burst any bubbles this long after but having read the LN volume with this part out of curiosity, that spoiler comment is misleading. It does happen how you figured it would, and he very much does fully forgive her. They just continue to be strangers because they can't change the past. Hell, the story even did both the "We lied to protect you" (from scandals, since the bio dad is in the entertainment industry) and "You said you didn't want to come with me" thing to boot
All that I mentioned happened in the tail end of the volume, too, which honestly makes it worse