The Pharisees held to Moses's teaching that a man could divorce his wife by issuing a bill of divorce. Jesus overruled Moses saying that he granted bills of divorce out of the hardness of hearts. So the pro-divorce and remarriage folks have more in common with the Pharisees, who complained when Jesus explained divorce and remarriage was adultery, that if that's the case, better to not marry at all. 

Why is it sad that the couples you describe didn't break their vows?  Surely their reward is in Heaven.