Spoilers aside, I agree with Keansor. Even if I was just using someone as a shield, I'd maybe try to be their for them when I know things are rough. Latte is too entrenched in her role as observer that she sometimes forgets that Ibelin is a person. She seems to kind of realize this with brown-hair(whose name I can't remember) after the stalker incident, so I had hoped she'd make a change and she could become actual friends with Ib.
Additionally, not telling Ib(or at least one of the fish) about the proposed betrayal seems very dangerous. If Peridot is trying to stick a wedge between you, she can do so from multiple angles.