A phenomenon of a broken relationship in which one partner longs for the other even after a breakup.
The respective girlfriend or boyfriend has left, but the other partner longs to be with them. Often stretches beyond what the relationship WAS to what it COULD HAVE BEEN. Normally, the partners have devoted a differing amount of emotional effort to the relationship.
The feelings of loss over the partner are the loss of a personal experience or feeling completion that has been removed through any break up. Emotional baggage and other idealistic concepts all add to the feeling of loss.