Having the courage to say it aloud...

This is hard for me. 
The past couple of months have been absolute agony.  Knowing what I know, seeing what I have seen, and realizing I'm too scared to share the secrets and feelings.  No one to ask for support.  Some days I just want to scream....I am destroyed inside.  My heart is broken.  I want to hide in a cave and never come out. 
But.....
But I know I have kids.  Two teenage boys who I am their rock and their world.  If I lose it, what will happen to them?  Who will take care of them?  Who will be there to fight through the pain I know they are suffering.  Two teenage boys who are in a critical and complicated stage of development.  I don't want to be the one responsible for putting that scar on their soul.
But...
I also know I am a role model to the young women I teach every year.  Trying to show them, you don't need to depend on someone else for your happiness.  Would admitting what I feel make me a hypocrite? 
But...
The day I received the text message from the other woman "informing me" of my husband's happiness with her.  My world crumbled inside. To yesterday, when she messaged me to inform me that I am personally responsible if anything happens to her.  That crumbled world burst into flames of anger.
All being told, in my heart I knew this was going on.  But maybe I was jaded.  I remember over the last three years saying.  "I know there is something going on, but I don't care.  I don't need him.  I can do it on my own."
Even...
"I think I am better off on my own."
And if it really was just that easy.  They were so happy, that she had resorted to blackmail by telling me.  It wasn't in that helpful movie way, like "Hey I fell for his bullshit, I think you should know. So sorry".  More like jealous...angry....why.  Oh, that's because he left her.  He told her he wouldn't leave his family.
I still don't understand the path that has lead me to this moment.  All I know is I am fed up.  And this is where my journey has different paths.
There is first my relationship with my husband....and where do we go from here?
Second, there is this woman who attacks me by social media....in the most cowardly way possible.  By making accounts and then blocking me so I can't respond.
Thirdly, there are my boys and what is best for them.
And finally, there is me and what I really want and desire in my heart.
All I do know, at this point is....I have to change this tsunami of pain and fear I have inside of me into something positive.  I know I am a survivor, and I have survived much worse than this.  But day and night it eats me up inside because I am afraid to let those few I trust know all the details.  I don't want to let those I love down or disappoint them. 
But where do I go from here?
This is the only healthy way I know of letting out all the pain I feel right now.