Hello 412Ron, I'd like to join with Anon guy 47 to say

So glad to hear you've found a therapist you respect, who can also work effectively with your wife. Getting a client's buy-in and commitment to the therapy process is a huge step, so it's great that both of you already have that.
It's also wise of you to refrain, like you're doing right now, from sharing BPD-specific info with your wife. BPD tends to impact the closest relationships the most -- those tend to be the most difficult and volatile, with the most emotional baggage -- so for a person to hear "you might have BPD" isn't always effective/positive coming from a spouse. Your therapist will know best if or when to raise that with her, so I hope you can rest assured that reading about it solo isn't "hiding something", it's you learning to be more effective in a non-triggering way for her. Telling her the label isn't as important as you building
new tools, skills, and approaches, to
turn down the temperature of the conflicts.
How old are your teens -- younger or older? How have they seemed to be doing with the home situation? And are they in any kind of therapy at all?
My husband's kids' mom has many BPD traits and behaviors. His kids are 16 & 18 now, and at least in our case, it's easier to navigate BPD in the family when the kids are older vs younger (though each family is different).
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This has meant staying with a partner who has been wildly out of line toward me and seems to build more and more hate toward me as the years go on while her family and social life seem to be eroding at a rapid pace. Several very close family members have actually moved out of state to get far away from her and the perpetual drama cycles that she used to pull them into. This has been very difficult on the entire family. We are near a breaking point again but this time is different. Now I am seeing things much differently and although I have lost a lot of hope for her to improve, I can at least make sense of her behavior and where our future might be headed.
Tell me some more about that. Is there a recurring core theme or topic of the conflicts/drama cycles? Something like "you never listen to me", or "you always take your family's side", or "you're cheating again and I know it", etc?
My ultimate hope is to be able to hold it together long enough that she can get the help she needs and learn how to manage this as a couple to hopefully bring happiness back into our marriage.
Learning how to manage as a couple is a good goal. It may help to think of BPD as a chronic disorder or long-term/permanent impairment. If your spouse used a wheelchair, there would be many things that she simply could not do, and hoping or expecting her to "do her fair share" of getting items off the top shelf, for example, would leave you resentful, exhausted, and frustrated. "I do 90% around here, why can't she do more?" Again, the wheelchair example is so obvious, that we can easily understand that it won't be a perfectly fair 50/50 relationship, but it's a choice to be in a relationship with someone who needs a wheelchair, and getting resentful about it doesn't help anything.
BPD is not as visible, but it is also significantly impairing and limiting... in the emotional/relational (vs physical) arena. Your W has impactful, significant, long-term emotional limitations, and seeing your relationship as an "emotional special needs" relationship may be a way to
radically accept the reality of your situation, grieve for what you don't get, and move towards better management of the real relationship as a couple.
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Take a look at some of those links, when you have a chance, and let us know what stands out to you;
-kells76