Ok, Maybe I missed something, but when the MC is talking to Julie on the bench, there's only one selectable option of "I forgive you, but...". I'm using the walkthrough, which seems to focus on Ahn, and even if I don't build on Ahn, that option is still the only one selectable. In later dialogue the MC says "we're just friends", I kinda stopped after that as I'd rather focus on Julie rather than Ahn... (edit: I finished the current content)
Edit: Ok, apparently having *any* points for Ahn takes you in this direction. Once the throuple route gets fixed I'll continue on, but if I had to chose, personally for me, Julie is the main target.