Why did Islam legislate divorce?

Divorce was legislated in Islam for necessary social purposes, such as resolving intractable disputes between spouses, as marriage aims for affection and mercy, not enmity. Ibn Sina mentioned that completely eliminating the causes of separation leads to harm and disorder, for dispositions may not be compatible, or one may be afflicted with an incompetent spouse, or the spouses may not cooperate in procreation. Therefore, there should be a way for separation, even if it should be made difficult. It should not be resorted to except after exhausting all means, and after attempts at reconciliation by family members and two arbitrators, as Allah Almighty says: "And live with them in kindness. For if you dislike them - perhaps you dislike a thing and Allah makes therein much good." And He says: "And if you fear dissension between the two, send an arbitrator from his people and an arbitrator from her people. If they both desire reconciliation, Allah will cause agreement between them." If these mediations are ineffective, then divorce becomes a solution, even though it is the most disliked permissible act to Allah. It should occur during a period of purity when no intercourse has taken place, followed by the waiting period, so that souls may change and hearts may reconcile.