While I really don't remember that talk exactly, Gracie plays people around her for various reasons so far known only to herself.
If I remember correctly, she was "angry" about Isabel occupying most of Antonio's time, leaving nothing for Gracie. While this isn't exactly sharing, the truth is that Antonio has also almost completely neglected his wife by now, too.
(Assuming that she knows what is going on, she has no real reason to be angry at her, at least not any more, so it must be an act)
Maybe she was testing him, how he would react and what he would do after the talk? Who's side he would take? Would he try to resolve the situation and how well?
Basically, a maturity test. Is he a boy who would just like to shove his dick in any hole he can, do anything to achieve that goal and run away when the situation gets serious? Or is he a man, able to reconcile two girls who detest each other because they were competing for an attention of a male?
I'm starting to remember that she was aware about the little sharade that locked them together into a closed space without an option to leave and played along despite of it.
![Roll eyes :rolleyes: :rolleyes:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
This kind of suggests that she was expecting something like this to happen.