Separation can relate to abandonment, marriage, friendship, career, or geographic upheaval. Many times, the subconscious impulses of personality are less mature in their problem-solving than the conscious, waking self. The function of ego is to filter these impulses so they do not get out into waking life. However, since the ego is turned off in sleeping, the immaturity of the id will have us walking away from our marriages, jobs, friendships, etc. at the drop of a hat.
Being separated is different than being quarantined, abandoned, or quitting in that it is often mutual. In dreams, other characters can be more cooperative, since it is our subconscious that is controlling their actions.
Who or what were you separated from in the dream, and did it seem like a permanent or temporary condition?
Was the separation easily decided, or was it gut-wrenching?