what a blow this must have felt like when you found it.
IMO, even if she did accidentally-on purpose leave that email there, she may not be ready yet to discuss the issue. This could have been her way of passively letting you know her thoughts because to actively do so would be too difficult.
I'd say for now, wait. Wait until you've spoken to a counselor, and wait to see if there are any changes in your W.
Just musing here, but I wonder how your wife would handle finding something you accidentally-on purpose wrote and left in the same manner? I'm not suggesting this, at least not for right now but I do wonder if this is perceived as a sort of "safe" route of communication.
Praying for you.
Me 46 H 56 M 22 yrs S22, D20, Twin Ss18
You teach people how to treat you by what you allow. What you stop. And what you reinforce. ~~~~~~~ A lack of boundaries invites a lack of respect.