Leave her alone and like Eric said don't try to get in her head.
Now be curious about why she asked about the mortgage balance, but don't ask her why she asked.
Listen don't assume anything, but if you're in this situation, she's leaning towards you being to blame and divorce as the answer.
SO DON'T ADD TO THE CHAOS OR JUSTIFICATION.
Just be quiet, act as if everything is fine in your world.
It's counter intuitive but thats what you have to do.
I made every mistake that an LBS could make.
They're pretty good at half truths at the beginning.
I'll give you my example, shortly after my bomb drop, my wife had a book on depression, the moment, the very moment, I mentioned it, instant denial and I defeated myself.
The key to this deal for both of you is time.
If I had do overs, maybe I'd still be divorced, but I wouldn't have crashed or paniced like I did.
The moment I went to short and sweet and not doing much, I started getting thank you's and waves.
Her mind, emotions, everything is all over the place.
Pray for her.
Do what I wasn't able to do at first.
Love her enough to leave her alone and get knee deep in other peoples threads too.
Protect yourself financially.
Listen for clues, "what would you do if we got a divorce?"
She's fishing, is there going to be a fight or not from you.
They have to run and justify.
Don't add to it.
Don't you leave the house and you watch those kids and pray.
No lengthy emails or texts.
They can't read past the first line anyway and if they do, they're looking for a reason to justify being angry at you.
Any contact you make it's going to ignite a fire and she's going to try to fix you, kids, anyone before she looks at herself.
It hurts and it hurts like hell, it may always hurt.
It isn't your wife as you knew her and she may not always be the way she is now.
Position yourself to be the better option.
The ones that hurt the most change the most and that's us as the LBS.
We get the hardwork.
We take on the burden of hurting for them, the heartbreak for ourselves, kids distanced from.
You have to be bigger than yourself for those kids.