Not really sure what context you are asking this question from, but I guess I think it is a load of garbage.
If people want to talk about the 'sanctity' of their own marriages, then that is their business. But when the concept is applied to marriage as a social institution, then I think it is utter bullshit.
Much like misanthrope, I don't think it means very much of anything in a general way. Every marriage is different, and everyone views its sacredness differently.
