We still believe that marriage is a sacred vow, but not when it comes to ending a life that the parents want to be spared.
I hope you understand that position.
The sanctity of marriage must be more than a one-sided thing which applies only to the declaration that a spouse would want to be dehydrated to death.
The husband here believed he could go on with a life with a girl friend, kids, etc., while at the same time deny her care to her parents by saying only he had the right to say what she would have wanted because he was a legal spouse/guardian.
Greer upheld that side of "marriage sanctity", but he ignored the statutes that disqualified the husband from Guardianship because of the husband's abandonment of the other side of "marriage sanctity".