It’s no secret Astarion hates himself. Like he deals with a lot of insecurities and self loathing. He just puts on an act of self confidence and narcissism to properly play the role of sexy vampire.
But I think a lot of people miss when he Ascends this gets so much worse. Not only does he still think he’s only good for sex and has nothing to offer beyond that. Now he’s a monster, not by force but by choice. He choose to become a monster. Now he’s expanded his act from sexy vampire to evil sexy vampire. He’s playing the villain because that’s what he thinks he is. And as we know he’s really not that great at acting.
I think it’s interesting everyone always talks about seeing through Astarion’s facade but when it comes to him ascending they’re so quick to fall for his act all over again.
There’s the line “if you stay with him he will always see you as degrading yourself” in his post ascension romance scene. A lot of people interpret it at face value as he hates and looks down on Tav. But I think it’s miss understood because he could never hate Tav as much as he hates himself. Infact I’d say he has Tav put up on the highest pedestal. He sees them as the kindest most caring person in the whole world. He adores them and holds them in the highest regard. That’s why them wanting to be with him so much they would even put themselves beneath him is the ultimate degradation. It’s also why he feels he has to turn them because he doesn’t believe there’s any reason they’d choose to stay with him of their own free will while at the same time he can’t bare to loose them. He can’t wrap his head around the idea that you could actually love a monster like him.
If you say you want freedom in the reunion party he panics. Why would you want freedom? To leave him? You want to leave him? Why? When he’s given you the only things he’s good for; luxury and sex. That’s the only reason you choose him in the first place. He’s desperate to make Tav happy. With out Tav he has nothing. He is nothing.
He hides his hurt and insecurities behind that mask of the villain, behind his facade of power and dominance. Under it all he’s still the frightened spawn cowering in the kennels. And there’s no one he’s more desperate to hide this from than Tav lest they realize their mistake of caring for him and leave.