If Hawke fulfilled the deal and helped Torpor to possess Feynriel, all dialogue options result in Anders: rivalry (+15). If a romance exists, Anders will refuse to be with someone who would sell out an innocent like Feynriel. He states that because they're both on such good terms with demons, that perhaps Merrill would be more responsive to their advances. This officially ends the romance.
Alternatively, if Hawke did not honor the deal and subsequently killed Torpor, a special choice is available, informing Anders that the demon is dead and that siding with him was just a ruse. This results in Anders: friendship (+20) (if Anders is at (+50) rivalry, all choices result in no approval change (Confirmed on PC)). Hawke can also proceed with the romance by telling him it was a ruse, regardless of how far it has progressed.
- The dialogue option with Justice in the Fade, despite being denoted by a "Breakup" icon, does not immediately end the romance. His romance scene remains queued for the next time you return to the Hawke Estate, and Friendly Concern sometimes becomes available as soon as you finish 'Night Terrors,' indicating that the romance is still active. It is not ended until you begin the dialogue for this quest back at Anders's Clinic and use any dialogue option besides "It was a ruse."
- Having Anders break up with you, if he had previously moved in, does not restore romance options with other companions. The breakup seems to be acknowledged, in that Varric will not talk about it and Leandra will not mention it, but the essential Flirt prompts for Fenris and Isabela remain disabled and Merrill does not visit you after Questioning Beliefs (Merrill). Effectively, once Anders moves in, all other options are null and void.
- This quest, along with all other "Night Terrors aftermath" quests, supersedes any other companion quests, aside from the initial "Visit" quests issued at the beginning of each Act. Anders is a notable exception, in that the dialogue for Dissent can actually take place before Visit Anders.