Morphing of the Ugly Cry

Last night I finally got around to watching the Book Theif.  I had been wanting to see it for a while, and my MIL just so happened to have it on her DVR while we're housesitting.  Andy was off playing soccer.  The girls were in bed. So I thought, why not watch it.
Let me say that I thought it was a beautiful and moving story.  I loved it, but then again I am a bit of a sucker for movies about girls who end up being writers.  Of course, the ending of the movie made me ugly cry, and I mean snot running down onto my lips and uncontrollable sobbing type of ugly crying.  Yes, I cried because of the sad ending.  Duh, of course it is sad; It's set in Nazi Germany! One small note of annoyance about the movie from a German speaker.  The foster mother in the movie constantly calls the protagonist girl "it."  In English, this really makes her sound like a jerk.  In German, calling a girl "it" is proper grammar and implies nothing.  I chalk this up to most likely a bad translation.
But then my cry morphed into something completely different.  The cry itself didn't exactly change, but the reason for the crying changed.  The movie is about children during the war, which is probably what set me off on this mental tangent.  It was just so hard for me to think about it while my own innocent children slept upstairs.  They are, as of yet, completely oblivious to the evil-ness that lurks in the world around them.  They have no idea how evil and callous the world really can be.  I was overwhelmed by the thought of their innocence as it compares to the ugly world that exists.
I was overwhelmed by the sheer weight of the thing that is parenthood.  I was overwhelmed at the responsibility we have to explain these kinds of things to our children.  How do you explain WWII to a child?  How do you talk about all the horrific monstrosities that have happened in this world and continue to happen?  I imagined their faces and the thoughts that will go through their mind, and the loss of innocence that will happen in that moment when they learn that the world can be a horrific place that is filled with REAL monsters that look like humans instead of being round green single eye-balled humorous characters voiced by Billy Chrystal.
I know that we have to tell them about it.  I know that we will find the right time.  Is it odd that I would rather we be the ones to break it to them?  When does this happen anyway?
Again, the cry morphed in a more ridiculous direction.  It's going too fast.  All the stupid cliches are TRUE and I HATE it.
It all goes too fast! TRUE
They're only little once. TRUE
It's just a phase. TRUE
They grow like weeds. TRUE
Etc etc etc.
Rarely do we take the time to reflect on this parenting ride as it is happening to us.  It really is a luxury to do so, and I fully acknowledge that.  I'm enjoying it, I swear.  But sometimes, just sometimes, the sheer weight of it bears down on me and I can't help but ugly cry, and that's ok.