I'm planning a trilogy where the first two books are companions told from the 1st-person perspectives of the protagonist(1st book) and a love interest/SO(2nd book), but for expositional purposes in the first novel I want to shift to the love interest's perspective for a conversation between the protagonist's primary SO and the 3nd partner, to provide some info about the protagonist. How would I do that effectively?
You don't need to worry about the perspective shift in the first book. Nust make sure the character in the second book directly references that ecen and then reveal their thoughts on it. You can adjust the character's behavior in the first book without directly addressing the cause of the behavioural shift.
