Abstinence does work and I'm not saying for a second that it should be downplayed; however, abstinence-only education does not work simply because it fails to really discourage kids from engaging in sexual activities.
The "sanctity" bit lies in allowing decent people to get out of marriages that were, for one reason or another, a big mistake. People change, sometimes drastically, and if that change is so colossal that the marriage is no longer working, the "you made a promise" argument holds little water.
A friend of mine's older sister got married about eight years ago. They lived together for about four years, and they were pretty happy. Then he lost his job right around the time she had their first child, which he claimed was "her fault" (he'd said he wasn't ready and he thinks she purposefully stopped taking birth control in order to get pregnant). He started hitting her. Eventually he got caught stealing cars and is currently in prison, having failed parole at least once already.
She may have made an oath to stand by him in sickness and in health, but which one of them broke that oath? Situations like this one are where divorce has sanctity.
If you were in my friend's sister's position, what would you do? Grit your teeth and wait for your abusive spouse to get out of prison? He's due out when their kid will be in the fifth or sixth grade, I can't remember which.
