The intensity of hurt in betrayal is directly proportional to the love we had. Why does betrayal hurt so much, so much so that some people lose desire to love?
When we love someone, that person becomes our own. There is always a sense of ownership. That is why one feels angry if one's loved one gets more involved with somebody else more than necessary. The sense of ownership and envy are essential to the process of love.
It is easy to say that when you love someone, give him or her freedom, space and so on. But does that ever happen? That does not happen because we are asking for equal or more commitment from our loved one compared to what we give. I care so much for you; you are also supposed to care equally. I never hurt you; you are also not supposed to hurt me.
We develop some kind of unsaid understanding. As the understanding becomes stronger, love becomes passionate and stronger. We all behave in this way in our life. Our loyalty to our school, our family, our country all comes out of this sense of commitment.
In love, the mind and the heart- logical and emotional feelings all are focused only on your object of love. It is an obsession when you think of nothing else but your loved one.
This is main cause of pain after betrayal. Because you never could believe that your loved one could betray you. You had considered them to be far better and lovable than anybody else.
How could he/she could this to me? That question keeps hammering your mind and you do not get any answer.
The grief of separation is equally strong. Your existence depended on your loved one and now he/she is no more there with you. That pain of separation is difficult to define in words. To avoid thinking about the loved one, people try many methods- join some group, do other activities, make new friends, and so on, but if the love was strong the person may remain a loner in a big crowd, because they have lost the foundation on which their life was being built.