John, other than the differences in our ages, your sitch is so familiar to me. Except my wife is still leaving, and I think yours might just be cake eating until the next EA. Are you two in counseling?
She's taking your temperature all the time, and you're making mistakes like you noticed.
This is the hard part of reconciling. Even with good boundaries, and transparency, unless you have a full time private eye watching her along with the NSA monitoring every potential communication device, you're stuck. If she wants to have an EA, (as she has many times before) all she has to do is wait til you drop your guard. She's been cake eating for a long long time, and also knows you and how you'll react.
That little voice in your head is a smart voice. It's something you should trust. And remember! Trust nothing she says, and only half of what she does.