How far are you in the main quest line?
I romanced Sera, but her card only changed when the last possible breakup moment was done. That moment was really late in the storyline (I don't wanna spoil you if you haven't finished a playthrough before so I won't get into any details).
This site here: http://dragonage.wikia.com/wiki/Dorian_Pavus#Romance details the romance between Dorian and the Inquisitor (caution, there are spoilers in there).
From what I gather, the cutscenes are mostly tied to approval rating. So doing judgements or continuing the main quest could trigger them later on.
