Can You Explain It To Me?

I really don't get it.. Why when we are really faithfull to someone, or we love that person sincerely, why we'll get hurts??!!! Can anyone explain to me why?? After what I did for you, why u treat me like this? Ignore me, blame me after all the fault that you done, tell everybody bad things bout me.. But actually i didn't did any of those thing,,, WHY?!CAN YOU EXPLAIN THAT TO ME?!?! CAN YOU?!?!