Legal separation can last forever, it is basically the last option before divorce. It is issued by a court order and either one of the spouses can change their mind and remove the legal separtion or continue with divorce. Legal separation is basicaly the last alternative before divorce, It gives spouses a chance to solve marital problems, take advanctage of medical benefits that they may not have if they were divorced, if religious beliefs conflict with divorce you are able to live separately and retain your marital status, etc....