Does anyone know if it's going to be an 'either or' situation between Yen & Triss or are you able to romance both?
Everything seems to indicate that you'll have to choose one.
Yen won't let you just plough Triss on the side, and I don't think CDPR's Triss will be okay with it either. I believe the devs have even said you'll have to play the game twice to see all of their scenes.