1. Acknowledge that they are an idiot that left the best thing that they could ever have.
2. Feel bad for thinking that way, but don't take it back.
3. Eat massive amounts of chocolate and ice cream (or other preferred comfort food) while laying in your bed and sobbing (sappy movies are optional or sappy books- which ever is preferred)
4. Write letters telling him all the words you could have said
5. Burn the letters and realize that they will never be said
6. Call your girl friends/guy friends
7. Go out on the town
8. Come home and cry because you miss them
9. Cry yourself to sleep
10. Repeat the process until it stops hurting.