There is no easy answer to this one. Whether or not you choose to divorce your spouse is a big personal decision, and no one can tell you what is right for you. However, here are some things to consider.
First, you haven't mentioned whether your wife has actually been diagnosed with BPD. There could be a variety of conditions that cause the symptoms you describe, and it is very important that she get a thorough assessment to determine what is going on.
The second thing to consider is that a considerable proportion of people with BPD do respond to treatment. So, before thinking of divorce, it may make sense to see if your wife is willing and able to engage in BPD treatments that may reduce her symptoms.
It is worth noting that even without treatment, the prognosis for someone with BPD can be quite good. Many people who have BPD do not meet criteria for the disorder within just a few years. So, if your wife does have BPD, this is not necessarily a life sentence.
Finally, people who have BPD often have much more intense symptoms when their relationships are in turmoil. It is possible that working to build a more stable relationship will help your wife experience more emotional stability. Of course, you need to think about whether you are willing to do this.
Giffin J. Family Experience of Borderline Personality Disorder. Australian and New Zealand Journal of Family Therapy. 29:133-138, 2008.
Skodol AE, Siever LJ, Livesley WJ, Gunderson JG, Pfohl B, & Widiger TA. “The Borderline Diagnosis II: Biology, Genetics, and Clinical Course.” Biological Psychiatry, 51:951-963, 2002.