Honest disagreement, open to real discussion, can energize a relationship, even where there are stark differences. But that can only happen in the context of arguing for an open philosophy that recognizes difference as natural, fundamental (e.g. democratic pluralism). But when you argue for and from a position of closed philosophies, a position that doesn’t recognize the validity of difference (e.g. most religious belief, platonism), then disagreement is always destructive.