what's mine is yours, and what's yours is mine

We may enjoy or make use of one another's resources or material possessions equally. Used especially in the context of marriage. Can also be said in the reverse order. A: "I would feel funny using the money you won to pay off my credit card debt." B: "Hey, what's mine is yours, and what's yours is mine, remember?" We share this office space and everything that's in it, Mary. What's mine is yours, and what's yours is mine!