The legislature in Mexico City (D.F.) is surprisingly progressive (for better or worse) compared to the United States. The local government recently made gay marriage legal, despite opposition from the Catholic Church. Now, they are debating the implementation of temporary marriage licenses. The legislators claim that since half of all marriages end in divorce within the first two years, the temporary marriage license would avoid these divorces.
The temporary marriage license would be issued for a minimum term of two years, but a longer term could be selected by the couple. When the contractual term ends, the marriage would end unless the couple decided to extend the marriage contract, no divorce needed. The legislators will vote on the proposed bill before the end of the year.
Although infrequently used, California allows couples to do something very similar by using contractual agreements to create something similar to a marriage, but technically not a marriage. Although the government would not recognize a marriage for tax purposes, a couple in California can contract to share property as community property for a definite term, share fiduciary duties that spouses share under the family code, etc. The State of California affirmed the freedom to contract rights similar to that in a marriage in Marvin v. Marvin (1976) 557 P.2d 106.
So, although Mexico City is calling it a “temporary marriage license,” you can pretty much do the same thing now in California by contract. Take that Mexico City.
You can read about Mexico City’s proposed law here, here, and here.