It all comes back to rational thought and then emotions. The rational thoughts know WHAT is best.. but the emotions are harded to convince!
I do understand. My emotional thoughts and feelings rule my life most of the time.
Have a look at the coping with emotions threads.. there are some good tips and tricks there to get you through the worst of it.
Am remember no one should be able to control your emotions (easier said than done). No one should be able to make you feel something that you wish not to - but we are human and well... nice people get hurt