Why on earth should YOU feel humiliated, when this behavior just reflects badly on your WIFE?
Take a deep breath - I know this feels really disrespectful (and it is). She obviously has been planning this for a while, and she was a coward to not tell you.
Do you know where she has moved? Did she take the kids with her? Furniture? You definitely need a lawyer ASAP to protect your rights as far as child custody goes.
Take the high road - just be factual, deal with the legal and financial logistics. If there is any chance of her returning (assuming you would even want her after a stunt like this) it will be better if you always stuck to the high road. Be firm - don't let her abuse you financially or with custody - but stay out of the mud. No blaming, no passive-aggressive stuff, just "If this is what you really want, I don't think you're making the right choice but it is your decision" and leave it at that.
Your lawyer can tell you whether in your state, her leaving the home constitutes any kind of abandonment - if you own your home, she may be giving up some rights to it in certain states. If she cleaned out bank accounts or took a lot of belongings she may have to reimburse you for those.
I know you feel like you just got sucker punched in the gut, but try to leave the emotional part out of it for the moment and just focus on the practical financial realities, for the sake of you and your kids. Keep what is in THEIR best interests foremost in your mind.
