I liked jealousy, especially with random people (like Tallis or Zevran), but I'm really not up for it if they start acting like Morrigan and Leliana over the Warden.
I know they already had issues so it's not a surprise, but it was more a lot more uncomfortable than Fenris and Anders. Even if they hate each other and Hawke was being serious with both of them, not keeping them warm in a lonely tent.
Also please, I know that it never happened in DA, but no "I never knew you were into women YOU WERE LEADING ME ON" thing. Especially if there isn't any "I'm just not into you" option. I hated that conversation with Kaidan in ME. Cortez in ME3 was totally fine, thought 
(But still no - "I like both!" option)
On a side-note, what I'd like more is a companion who addresses their problem about what the PC is doing.
One thing I didn't like about romancing Sebastian is that he expected me to never flirt to anyone even before we ever met.
Like dude, really, just tell me or something.
Especially because the Blooming Rose, Zevran and Tallis instead were totally fine and there is no way to know in-game that he is fine about you being with everyone you want as long as your heart belongs to him only.