When I read all the posts on here, I feel great sympathy for every one in this terrible situation. I thought I was in a somewhat unique and fortunate situation in that my ex was officially diagnosed with BPD and is, at least for the moment, involved in BPD- specific therapy. However, I'm starting to think that's also a little bit of a curse for me. I can only assume her therapist has stressed to her how important it is that she not rebound into another relationship. I also assume she's following this advice, at least for now, because she is still trying to recycle me. Sending me messages about how she misses me; a half dozen or so emails over 3 weeks. I've only responded to one because she mentioned her mail being forwarded and I asked for her new addresss. I haven't responded to ANYthing personal. I do still read her messages. The next step is not doing that. I know that's what I need to do. I know if she does rebound, I'll be completely out of the picture and that's what I need. Such ridiculous mixed feelings... . My logical side wants her to find someone else so I'm "dead to her". My sympathetic side wants her to stay single and work on herself. The problem is, it's not just my sympathetic side. There's also part of me that wants her to "get better" and come back. I need that part of me to shut up and go away.
First of all, I think a certain percentage of people here on this forum would give this 'ex' a try again. Why? 1) She's in therapy 2) love/clinging phase is awesome. So for that I would already want to tell you, well done in regards of this detachment of yours. It seems you already went through a few phases of detachment!
The question, either full neglecting/NC or sending an email wishing her best of luck is something I can't answer. I know if I would be in your situation I would try again and rebound with the girl.