Try this visual technique to stop thinking about your ex. Hand your coat and a garment that reminds you of your ex facing each other in your closet with the door open. Let the coat and the garment face each other in the closet for a week or more.
The garment should be something that you do not mind donating to charity. It could be a sweater of his favorite color. Let the garment drop to the floor of your closet after a while and then leave it there. Do not pick the garment up.
Have your computer face the closet and every so often look at your coat and the garment that is no longer hanging up beside your coat.
Get the visuals of your coat without the garment but do not feel heartbroken but feel relieved and independent. After you are sure that you are over your ex, donate the garment to charity and then move on.
The independent coat now without the garment in the closet will symbolize you as being able to move on without your ex. This simple exercise in visuals will train you to get used to being independent and able to move on.