Hi Lee & JJ! I hope you don't mind my "dropping ",but I've been following your posts and when James John elaborated on his step daughter, I felt I might be able to add something.
I've worked with Borderlines for years and your description is right on target. This is a very disturbed individual who will need life long therapy and medication. It's unfortunate that she is part of the family dynamic and it is a constant stress.But,as you know we have to deal with the "cards we are dealt".
Our 16 yr old boy is ADD with impulsivity features and he keeps us on our toes constantly. It takes tremendous energy to deal with his behavior, which doesn't leave much for our marital relationship. However,we are pulling together and learning strategies to help our son cope with his disorder.
JJ our son's problems are "minor" compared to what you and your wife have to deal with in step daughter. I hope you are "detaching" from her pathology as much as posssible as she will be creating scenarios that will keep her in the center of everyone's attention. There are treatment programs that deal specifically with borderlines.
You are doing a wonderful job of holding your marriage together in the face of such serious challenges.Make sure you and your wife are taking care of your own needs.
Lee...your H is on his way back to you. Actions speak louder than words. Jenny