(1)    After April 4, 1984, and before their determination date, spouses or unmarried persons who subsequently marry each other may execute a marital property agreement under s. 766.58, which is intended to apply only after their determination date, to the same extent that persons may execute a marital property agreement under s. 766.58 after their determination date. The marital property agreement does not apply before the persons’ determination date. Upon application, the marital property agreement has the same effect as if executed after the persons’ determination date.

   (2)   Notwithstanding the execution of the marital property agreement before the persons’ determination date and notwithstanding the January 1, 1986, effective date of 1983 Wisconsin Act 186 and 1985 Wisconsin Act 37, the law in effect on the date when the marital property agreement applies, not on the date of execution of the marital property agreement, applies to the execution and enforceability or other legal effect of the marital property agreement.

   (3)   A document executed by spouses or unmarried persons who subsequently marry each other which is intended to apply in whole or in part before their determination date is governed by s. 766.58 (12).