First Playthrough: Human Female; Elemental Force Mage (or the equivalent hopefully imported from DAII via The Keep) named Audrianna will romance Josephine
Second Playthrough: Human Female Elemental Arcane Mage (or equiv.) named Noria (imported via the keep as she was in DA II to the best of my memory) will romance Vivienne (if she is available) if not, then I will romance Sera (not as a 'second choice' but on the same level of interest as simply another option)
Third Playthrough: Elven Female Rogue Archer named "Nyah" ( and modeled as closely as is possible after Evangeline Lily's character in The Hobbit: The Desolation of Smaug) who will most definitely romance Sera with exclusivity
Fourth Playthrough: Elven Female Mage (Spec. Unknown) will romance Sera
Fifth playthrough: Human Male Mage (Knight Enchanter) will romance Cassandra (cause she's a hottie and she deserves some TLC)
Sixth Playthrough: Human Male Rogue Archer will romance Vivienne
Seventh Playthrough: Human Male Mage will cast his spell over all the ladies (except Sera because she....prefers a woman's touch, haha)
Eighth play-through: Elven Male Mage will not romance anyone but have a lot of BFFs of both genders.
Ninth play-through: I've never ever played as a Dwarf before, so I might just play as a female Dwarf warrior (and see if I can't find out what all the fuss about Varric's chest hair is)....Though my ulterior motive is to do my best to make Bianca jealous and (hopefully) he'll forget about putting his hands all over her....many curves
Then I will start all over again from the top. But my two "canon" playthroughs will be Female mages, one who romances Vivienne, or more likely Sera, and the other Josephine