Early on in my situation I had lots of trouble with boundaries. I understood the concept, I knew I wanted to set and enforce them but never seemed to be able to. I understand it's not an easy thing to do however it will help you and perhaps help your situation.
For me, sometimes it helps to remove the emotion of the situation and look at things in a different way. If you had a co-worker that was constantly rummaging through your desk while you were at lunch what would you do? You would need to set a boundary in a firm yet polite fashion that this will not continue, your personal space is not to be touched or tampered with and you will no longer accept such behavior. Bam - boundary set. You made your boundary clear. If this continued despite you setting a boundary then and only then would you escalate the issue to management or human resources.
That all sounds reasonable, right? If you apply the same line of thought to setting boundaries with your W things will get easier for you. Set the boundary in a kind and polite fashion. If she chooses not to honor the boundary then escalate the enforcement of the boundary.
Using the 1000.00 situation as an example - having the boundary talk about coming up with a mutual agreeable financial plan would have been step 1. It actually could have opened up communication for the both of you in a new way. But you got pissed and frustrated and went right for the gut, the scare tactic and the big dramatic finish before you even tried to set a reasonable boundary.
Thinking back to the hypothetical work situation I posted above you would not be able to "go for the gut" and use scare tactics before attempting to set a firm boundary with your co-worker. It would deem you unprofessional and chances are you could have ramifications simply due to the way you handled things. Your first attempt with co-worker would be "Co-worker, when I am not here you are not to touch my personal things or my desk under any circumstance without my permission. If you are unable to respect my personal space I will remain professional but will have to enforce this by escalating to boss/HR".
That would be reasonable. You would not threaten to kick his ass in the parking lot w/o at least *trying* to set a boundary as you could lose your job or even be arrested. With your W though you bypassed the boundary and went right for the "ass kicking" because she didn't respond as you hoped.
This is a learning process and I think from this incident alone you can learn an awful lot that will be helpful to you.
