How do people change??

I will never be able to understand how do people change. Those who once cared so deeply, and with so much affection, when they leave, they are not even bothered about your feelings or about anything. You keep wondering if this is the person you actually fell in love with. Your tears, your requests and your feelings everything goes in vain. You are begging not because you don’t care about your self respect or you believe that it was your fault. You beg because you want to save the relationship, save what truly mattered. I regret that I begged them to stay. I simply validated their feelings by doing that; made them believe that they are right in doing what they are doing.