I assume that you have experienced a relationship loss, and for that I am sorry. It's natural to feel anger when you lose someone important in your life, whether through death, breakup or divorce, or physical separation, as in when one partner moves away.
Several ideas for constructively dealing with one's anger include:
1) practicing 7-7-7 relaxation breathing: inhale deeply for 7 seconds, hold it for 7 seconds, and exhale completely for 7 seconds; repeat
2) exercise, such as running, walking, yoga, basketball
3) talk it out with a friend or counselor
4) write about your feelings in a journal or do creative writing
5) change your environment/take a "timeout."
6) humor - watch funny movies or go to a comedy club
7) get plenty of sleep
8) listen to upbeat music such as this Positive Vibe Playlist: