Hi.
How long does it take? Does it ever really get better? She is trying hard and sees counselor bi weekly.
The time varies. What sort of counseling is your wife getting?
Some people do recover, with recovery being defined as getting to a point where the BPD behaviors are no longer pervasive and interfere with a persons life (very paraphrased version that I just wrote there). The biggest indicators for a good outcome are 1. the desire to get better and 2. a good strong support system. So yes, things can get better.
What sort of challenges are you facing? Is there a particular behavior that is more challenging than others?