An ex-best friend is someone who was once a close friend but is no longer. The term can be used to describe a former best friend who has drifted apart due to changes in circumstances, values, or interests. It can also refer to a former best friend who has been estranged due to a falling out or conflict.
Losing a best friend can be a painful experience. We may feel betrayed, angry, lonely, and confused. We may also wonder what we did wrong and if we could have done anything to prevent the friendship from ending.