I can only argue for legal divorce. Without the option of divorce marriage can become a prison or form of enslavement, especially for women. Men have always had more freedom and most countries do not criticize men for straying from a marriage. If people are unhappy they fight with each other and look for sexual relationships outside of marriage. This opens people up to the dangers of sexually transmitted disease that can be brought back to the spouse (think about the AIDs crisis in India and China). I think women and children suffer the most in iron clad marriages. Unhappy men are more likely to be violent and take out their frustrations on those who are nearby and weaker. Women can also take out their unhappiness and frustrations on their children. I am not a religious person, so I cannot even give you a religious reason that people should be forced to live together if they are miserable. I think some religions like it when people are miserable and think it builds spiritual character, but I don't agree. Life is too short to trapped in an unhappy marriage, especially if once someone is free they have a new chance to find love.