Legal separation (sometimes "separate maintenance") is a possible step towards divorce. A couple is officially legally separated only if they have successfully petitioned a court to recognize their separation; simply living apart does not constitute separation for these purposes, though it is a form of separation and is often a psychological necessity during divorce proceedings. The primary reason for a legal separation is the rights and duties that accompany it. For example, one spouse, usually the wife, receives financial support during the separation. The agreement can also specify issues of custody and visitation.
Legal separation does not necessarily lead to divorce. The couple may reconcile, in which case they need do nothing in order to remain married. If, however, they do not reconcile and wish to divorce after the statutory time period, they must explicitly file for divorce.
A period of legal separation may serve as sufficient grounds for divorce. Some states require a period of separation before divorce, though the length of this varies.