Don't talk to Halsin, don't hire the twins and it's not an issue
The issue for people is that although they can avoid this on their playthrough, it is still a part of their characterisation. And in this case, if taken seriously, this characterisation shows that under certain circumstances Shadowheart would show great disrespect towards her romantic partner, her true love. In case of Halsin and twins for example, she would push for including Halsin and voice her fantasies about him, without making sure that her partner approves of it.
Do you have a youtube link to that moment? I'll respond when I've viewed the scene.
Starts from 3:51. All of this can happen even if player rejected Halsin outright.
