For the people interested:
- you can romance both SH and Halsin.
SH seemingly has a problem with Karlach in particular (or it's bugged/people did it wrong). You're not a throuple in this case. Threesomes appear to not be in the game at all, claims of discrimination against straight men (and curiously not lesbians) notwithstanding.
Weirdly enough, Karlach might be strictly monogamous after she's cured. That could be the problem (not SH). I still can't find enough info on Karlach's final ending and proclivities. You can romance both SH and Karlach for a time, but not forever. SH will break it off with you and not meanly.
Lae'Zel or Jaheira and SH might work, which is... 3/4 women. Unknown
