Why is it when you get out of a relationship thats not working and you know that you don't need to be in it that you keep dwelling on it and thinking about it? How long will the thoughts last? I find myself doing this and I know I'm better off but the thoughts keep going through my mind about it all, it drives me nuts and I don't why! Can someone explain this?
As in anything that comes to an end, it is a grieving process. Even though you know you do not want to be in the relationship, in part, it makes you feel like you have failed in some way.
Denial - "No way, this isn't happening"
Anger - "Well Screw you I hate you all."
Bargaining - "I will do anything to work it out"
Depression - "How can I go on without them"
Acceptance - "I am better off and life WILL be ok"
Recognizing the state you in, excepting that it IS truly better to be out of the relationship, that because it ended does not mean you failed, are the keys to getting over anything like that. Like you said, You Know your Better Off, just try not to put so much pressure on yourself to get over it too quickly, like anything, it takes time.