To grieve or not to grieve

Why do people allow others to take their power and hold on to it for long periods of time?
When you break up with someone it hurts, granted. We grieve for a while and then we are supposed to move on.
How long is long enough? There are many variables. As we are all individuals with different tolerance levels, and each liaison is different, thus, the length of time and depth of hurt vary.
Experts say it should take half of the time we invested into the union. This means half of the time the individual invests not the couple. Sounds all too clinical and mathematical to me.
Shouldn't we just realise it was not meant to be? If the other party hurts you by doing what is morally wrong or by incorrect behaviour on our social judgment scale, this obviously hurts but the longer we hold on to this the longer we delay our healing and the more power we afford the abuser. It all boils down to the fact that the longer we hurt equals the greater power they had over us. Is this then a weakness in our own character?
These people should not be able to command any more attention from you; they have obviously moved on. DO NOT allow this to happen as they do not deserve this recognition day in day out. Do you believe they care or even consider "OH! they might be hurting today. I will give them a call to comfort them". It's time to move on and find someone who will comfort you and care for you, freely, the way you deserve. NO length of time now, will ever prevent you from hurting again. We will all experience some form of rejection in our life... if not from a person, from a job, the bank, our children etc etc.
Life is too short to dwell on this person who betrayed us. Just think, we spend so much time trying to reconcile the why, what and who went wrong; we try to lay blame. There is no answer... it just did not work... it was not meant to be.
You did what you did at the time. You cannot turn back the clock and have a do over. Life is not like that. All the analysing in the world will NOT prevent things from going sour again. We make choices and right or wrong, shit happens.
So, no more arguments, get of your butt and get back into life. As you are now, you are no good to anyone and we need good people out there so we other good people have more potential partners to choose from.