It sounds like your own LBS fog is lifting and you're starting to see her for who she is now. This whole ordeal has changed you whether you like to admit it or not. You're beginning to see what a disruptive force she is on the harmony you have built up with your D. Carry on observing objectively. Watch her actions and she will reveal herself.
I'm divided on the idea of whether you made a mistake in letting her return. It was a mistake because you let her back too soon with little true change or commitment on her part. Perhaps it was not a mistake because you're getting a first-hand view of who she has become. This may help you achieve clarity to make an unbiased decision on how to proceed.
I know you've been doing a lot of thinking and you're battling your desires with what logic is telling you. Take some time to think about what YOU really want. List out your criteria of what you ideally expect from her, then evaluate each item and see if it is realistic or not.
Take your time and think LOGICALLY about it. Speak to your D. Observe your D and see if W's presence is affecting her adversely. You still have a lot of introspection to go through bud.
M:11 | T:12 | Status: Married 4C's of WAS communication: Cool, Calm, Collected and CONFIDENT
