im wondering can you have relationships with multiple characters or just with rosette, when i tried that the game kinda called me "greedy" so i thinks a bad thing in this game but im not sure....
It's not that it's frowned upon to do so; the creator hasn't yet added anything distinctive that would allow you to form a "relationship" with other characters, although the game does "penalize" you if you take certain actions and don't follow the "script" of the story.
That really depends on each person's conscience and their playstyle. Having relationships with characters other than Rosette is frowned upon by many people, but you should follow whatever path you want.