Can a prenuptial agreement keep pre-existing separate debt separate

A prenuptial can be negotiated by the parties by their respective lawyers. Each of you must have separate lawyers to make the document enforceable. The prenuptial can segregate pre-marital debt and insulate the parties from eachother's pre-marital obligations. There is nothing in the law that says once all of the debts are paid in full that the parties can't tear up the prenuptial agreement or execute a document voiding it. In fact, your attorney may negotiate a clause in the prenuptial agreement that triggers the "sunset" of the agreement once the debts are wiped out.