So if they had thought about their split, maybe they would have decided differently, maybe Lisa would have thought, "Maybe the inheritance can stay separate," and saved for a day when they might actually need it.
De haber pensado en la separación, quizás habrían decidido otra cosa, tal vez Lisa habría pensado: "La herencia podría permanecer separada", ahorrada para algún día  que podamos necesitarla.