why

hi, am shoked from a story that happened to someone . it's hard to be deceived not for a while but for a long time by your beloved and the worst is that person doesn't deserve it. why some people are so cruel even with whom treat them good.why?really , i tried to make myself , by imagination, in their place just to see how they can have more than face and pretend to be good . how hey can feel unfaithful.the worst in this situation is to be unfaithful with who really care about you and faithful to the commitment