I can't find any evidence of this anywhere online where she says that about Karlach. The only thing I've seen people say is SH saying something like "I wish I was the one to give you that spring in your step" and then ending the romance.
And doesn't it seem a bit strange that this would only happen with Karlach? Why specifically her? I know she's flirted/complimented her but I'm pretty sure she flirted with Astarion and Gale too. Plus, if it were actual polyamory, why not ask to join in instead? Maybe Karlach wants her attention too..
In act 2, after you get Karlach's 2nd upgrade, she basically says she wants to touch everything and everyone lol and she'll kiss multiple faces. They could have made that the perfect opening for a poly/open relationship because they know Karlach's time is limited. Karlach is legitimately looking to have as much fun as she can.
They could have at least given an option to ask Karlach. Isn't it her who should ultimately decide what she needs and is comfortable with?
It's their endings that don't necessarily match up though, depending on your choices in SH's story especially. So maybe that's what the problem is really. You'd probably have to choose between them anyway.
Looks like I'll have to do another playthrough and romance them both to see for myself. I wish there was a list somewhere, of all the companion lines to the player, to make this easier lol
I think it would be great if there were a legitimate option like this though, because there isn't any poly/casual sex option for lesbians or straight men currently.
There is such text if you start romancing SH and Karlach and choose Karlach at some point.
Player: I'm not a swan - I don't mate for life. I want to be with you and Karlach. Shadowheart: I admire your ambition - and your belief in your own stamina - but Karlach deserves to have you to herself. And perhaps there's yet someone out there for me... Shadowheart: And don't worry about me - I'll manage, one way or another. But I'll remember our little moments together fondly - they're amongst the few good memories I can lay claim to.
I guess SH generally prefers monogamous relationship. She accepts player's affair with Halsin since she is aware of wood elf nature (from wiki: Wood elven romantic and sexual relationships were often polyamorous in nature, members of the race freely engaging or ceasing relations with new partners.) very similar to Mizora case.
