What is so complicated with this idea?

Two different players play the game.

Player 1 says and does certain things and Halsin's story and personality changes to adapt to this.

Player 2 says and does other things and Halsin's story and personality changes to adapt to this instead.

Player 1 and player 2 are never in the same game, they literally have nothing to do with one another.

How is player 1 in any way negatively affected by the options and choices available to player 2? And Halsin cannot feel either way about it, because he is not a real person.