I know we've talked about this before, but since it came up again...
I don't think Sapkowski intended for Geralt and Yennefer to just die in the books. I think he wanted to retire them, to a world where they would not be bothered. I get this impression not only from the whole situation with Ciri, Ihuarraquax and the boat, but also from Ciri's words to Gallahad afterwards. I don't think they died.
Now CDPR definitely does not think Geralt and Yennefer died. They brought them back and made 3 games about them. If someone dies in the Witcher Universe, he stays dead, or comes back as a wraith. He doesn't come back as a living person.
I agree with Vigilance, that at this point, Geralt's and Yennefer's relationship is not just about Geralt's wish. The characters have been through so much together, and they have someone that unites them more than anything. And that is Ciri. But the wish is still very important. Since it is about Destiny. Geralt and Destiny go way back, I sometimes think he messes with Destiny so much, in an attempt to prove that it doesn't exist. Hasn't worked out that well for him, at least in his World.
At this point this is what we know.
Yennefer was with Emhyr, maybe a prisoner, maybe not, for quite some time. But she is allowed to go free, unless magically controlled which I doubt. If CDPR's Yennefer is anything like Sapkowski's then I don't think she works for Emhyr. Maybe she works with him for the time being, but definitely not for him. As long as he helps her locate Ciri, she would work with him. That is, if she knows about Ciri.
Same applies to Geralt. He will do anything to protect Ciri first. Yennefer comes after that.
Now Triss is not exactly like that. Triss will give her life to protect either of the three, be it Geralt, Ciri or even Yennefer. She is brave, because she is notorious for not being brave. Anyway. But she is also "loyal" to the North. She will fight for the North one way or another, and she will most definitely be against Emhyr. That makes her, somewhat ineffective, as far as finding and helping Ciri goes. I think she is going to be torn, without a clear goal in mind, just as she was in the books. I bet she will do something really important eventually.
Yet we have to take into consideration the potential character development she had mostly in TW1 with Alvin, and her current situation. She is a former adviser, to a fallen Kingdom. She doesn't have any political influence. And she is out of the "dismantled" Lodge. Her options are limited, so maybe she will decide to fully support Geralt in his quest.
And that could be how the love triangle becomes more "possible" in my head. Because Yennefer will not follow Geralt. She might help him from time to time, but she will do things her own way. She will run off and track down Ciri on her own, because everyone else is slowing her down. And she is kind of right, considering her skills.
So I don't think it will be Emhyr - Yennefer versus Triss - Lodge. All three characters care for Ciri. Her safety is the most important thing. The romance dynamics in that quest can fluctuate a lot as the game goes on.
Thing is, if Yennefer finds out about Geralt and Triss, she will probably be furious. And she will find out. The King's witcher was fucking the Royal Adviser, that was no secret. But hey, Geralt did have amnesia.
I just hope we get to see the characters more than what we saw of them in the previous games. Game size will definitely play a role, but you know..
Hopefully we won't see a character at the start of the game, and then meet them again, 40 hours down the road for a quick summary of their adventures. I mean sure I'd like to see something like that, but also spending some time developing the relationship between two characters, would be awesome. Like the small chat Geralt had with his friends in Flotsam before the Kayran attacked.