I know women who were raped by their husbands.
I know women who were beaten by their husbands.
I know men who were cheated on by their wives.
I know too many people who were in horrible situations, to think that they wouldn't be allowed to leave these situations is a horrible thought.
Divorce exsists because sometimes people change, sometimes people lie about who they really are.. and you shouldn't have to die or be killed by the person you swore your vows to just to make the "until death" part stick.
For others who aren't suffering from domestic abuse or emotional and mental torture - I do believe some courts encourage marriage counsiling first, but I could be wrong.