Just an aside - in my case anyway, romancing Shadowheart was pointless. A caveat - hetero cis male here - so there's that. A kiss, some regrets the next day - meh.
It's the same scene if you play a female character.
That scene also has a visual bug currently (unless it was fixed since patch #1, I haven't replayed the scene since). The reason she ask if it was painful is
because her weird magic is supposed to flare up during the kiss according to dev notes for the scene.
It slightly change the context of the regrets the day after.
