Hello, hegrid &

I'm so sorry for the frustration, sadness and stress you are dealing with, and know just how difficult and painful a relationship with someone with BPD can be... .Especially with a child involved, it's always wise to try to figure out how to do the right thing for everyone. Please check out the links I'm mentioning, below, before posting on the Leaving Board, hegrid... .
I know you are thinking of leaving your wife, but if you are still living with her as Husband and Wife, a great place to start in order to understand her disorder and to figure out how to deal with it is to check out every single
link to the right-hand side of this page.
The Lessons and the other links will give you a great primer on how your wife's mind works, and what you can do to make things between the 2 of you better--whether you stay or leave, doing that can only benefit your situation, for you and your child (and your wife).
Have you checked out the
Feature Articles located under the 4 photos at the top of the Staying Board's thread listing page? Every one of them is perfect for learning what you need right now to figure out what to do and how to do it, and I highly recommend
What Does it Take to Be in a Relationship to you to read while you are figuring out your next step.
Since you are still part of this relationship, learning what you can to stop making things worse between the 2 of you--whether you will ever be able to see things get better enough for you to eventually stay or not--will be helpful to not only you and your wife, but also your child