As somebody who in my second marriage insisted on a prenuptial agreement I can also testify that sometimes it is an act of love to chart the exit strategy before you enter the union in order to make sure that not only you but your partner as well knows that there will be no World War III should hearts and minds for any sad reason change.
The idea of the sacred is quite simply one of the most conservative notions in any culture because it seeks to turn other ideas - uncertainty progress change - into crimes.