That song you hear before Rivington is "I want to live" if I remember correctly.
The instrumental version is often played when you're in camp, but you can hear the lyrics when you go to Astarion's tent.
The lyrics do seem to have a link with Astarion, but the composer has stated in a tweet that this song is the player's theme, so it about your trials and tribulations.
Really sorry to hear that, Astarion is much more suited to that song, and so it's just a +1 to marysue for the player.
The level of marysue in BG3 is still relatively tolerable, it can be worse (for example, in Dragon Age: Inquisition this level was so off the charts that it made the game so stupid at one point that it was impossible to continue), but still... About DU we can still talk about some trials and tribulations, but Tav has the same problem with larvae as other companions, Tav no one will put a wooden stake in their guts for fun, no one will surrender Gur to death, it is not written about Tav in all "paladin codes" that it is a monster that can be killed. Even if Tav is evil, the world is still nowhere near as dangerous to them as it is to Astarion, and what Astarion has been through doesn't compare to Tav's "tribulations". And Astarion really really wants to live, his lust for life, no matter what, is amazing. This used to be my favorite song, the composer's statement definitely cheapened it for me. Unless I try to expunge this new information from my memory and leave the previous perception of the tune in my headcanon...
