Oh Hamster, I'm sorry you are going thru this! I know impulsivity is a tough one to overcome. You could try the rubber band on the wrist trick, snap it every time you even think of contacting him. Put an extra large sticky note on your computer screen that says ABSOLUTELY NOT!, just to give you a second longer to think. As for the phone, delete his number so you can't quick dial him, and while you punch in his number the long way, you might have a second or two to rethink it. Mostly, tho, I think the rubberband snap every time you think about it will work best.