Marriage is indeed a sacred bond that brings together a man and a woman by virtue of the teachings of the Qur'an and the Sunnah. Indeed, Allah Almighty describes this relationship is as though one is a garment to the other; “...They are raiment for you and ye are raiment for them...” (Al-Baqarah: 187), thus illustrating the closeness, affection, warmth and love of one for the other.
But what should be done in cases of irreparable breakdown of relationships or in other cases love disappears and life brings about challenges that are too hard for some marriages to resist.
In this case Islam provides a way-out by allowing a divorce so each couple have another chance to start a new happy life with some one else than a miserable marriage, which would definitely lead to infidelity or depression. This does not mean that Islam - in its quest for people's happiness - makes divorce an easy option, but it comes as the last alternative after serious attempts for reconciliations.
The Prophet (peace and blessings be upon him) said: "Among lawful things, divorce is most hated by Allah." (Reported by Abu Dawud).
The spouses should avoid divorce as much as possible. If they have difficulties and problems they should try to work out their differences and seek help from their relatives, friends or professional counselors.
And if ye fear a breech between them twain (the man and wife), appoint an arbiter from his folk and an arbiter from her folk. If they desire amendment Allah will make them of one mind. Lo! Allah is ever Knower, Aware. (An-Nisa':35)
However, if the differences are irreconcilable then divorce is permissible, but it should be done in a decent manner.
References: Islamonline and other sites