Talaniman said it all:
1. ACCEPT IT'S OVER, no matter what your heart might tell you.
2. Grieve, you have lost an important part of your life, you must allow time for this step or you'll never get over the ex.
3. Move on... long process that for some never really ends, but you will become a fully functional person again, open to new experiences and relationship
I don't think the feelings for an ex you truly loved ever go away, but by using NC, you can dull the stabbing pain of loss