We don't get upset simply because someone lies, cheats and breaks our trust. In my view, we become upset because we can't trust that person (and folks like him/her) ever again. It's the violation and loss of our innocence that hurts us deep inside, for a short duration at least. Yet, when we rise from that freaky fall, we discover that we're stronger than ever before. It's true that what doesn't kill us often makes us stronger. So strange as it may sound, we should be thankful to that deceiving person, who offered us the golden opportunity in disguise - to eliminate our weakest links and to strengthen ourselves beyond our normal limitations. Cheers!
Deodatta V. Shenai-Khatkhate