Astarion is my favorite romance so far and you all have some very interesting thoughts about it!
I know I am concerned about how it all might play out. I am hoping he will genuinely fall in love with the PC. When I played DOS2 I know I was super disappointed in the Red Prince romance and I just don't want that to happen again. :P
Though during the Astarion 'star gazing' scene I think he does look a little smitten with the PC.