Yet completely fitting.
Throughout the game it's been hinted at that relationships and anything casual is actually looked down upon by Shar because it means you're not doing her bidding. They needed to find excuses or do it secretly. The only time this narrative is flipped upside down is when you cheat on Mizora, where the writing is inconsistent with the rest of the dialogue in the game.
This is why she doesn't do jack in act 1 and act 2. She knows Shar wouldn't approve. But she herself wants it, that's why she's conflicted between choosing you and Shar, and unhappy when you do anything with another companion.
Then you get the Nightsong choice. In act 3, you have Sharran or Selunite Shadowheart.
Both want you for themselves, so neither should want to share you whatsoever; not with Halsin, not with the drows and not with Mizora. The only difference is that the Sharran version needs to find an excuse to get down with you because she doesn't want to piss off Shar (hence she calls it an exception), whereas the Selunite version will devote her everything to you (move in together, start a family) because that's what she personally wanted all along and now Shar's not there to stop her.
The only thing that strays from his own writing here is Halsin, the drows and Mizora. Three completely avoidable and short dialogues.
I just wanna bring this back as an appreciation post. I really feel like this hit the nail on the head when it comes to SH and her complete 180 regarding Halsin, drow, etc. This one post brought so much clarity to the situation I feel. So kudos to Michieltjuhh for posting it