Dreaming about a former partner can signify a need to heal residual feelings from the old relationship, a desire for specific qualities missing from a new relationship or a longing to revisit simpler times in one's past. Such dreams are normal, especially after ending a committed relationship.
The subconscious uses dream time to process and heal sadness, regret, guilt, anger or other unexpressed emotions for which there are no ready outlet during waking hours. This is particularly true if there were important matters left unsaid in a former relationship. The beginning of a new relationship can trigger dreams of an old flame as the subconscious mind tries to stack the qualities and characteristics of the new partner against the previous one.
These dreams can also be the mind's way of signaling that all is not well in a current relationship. The subconscious sometimes tries to fill an important void such as a lack of intimacy, honesty or trust by dreaming about a former lover who possessed these qualities. The appearance of a partner from adolescence, especially one's first love, can signify a longing for lost innocence and freedom from the constraints of adulthood. Dreaming of an ex partner does not always mean one should resurrect the relationship. These dreams are the mind's way of cleaning house and ridding itself of any remaining baggage.