Hi timandkat,
Welcome aboard. You came to the right place for support and resources. You will find that there are many of us who are going through similar situations with their significant other. Posting here really helps.
I understand how unbearable it is coping with the erratic and confusing behaviors of BPD. The rollercoaster behavior of a person with BPD (pwBPD) can make anyone feel frustrated or overwhelmed.
It is great that you are taking the opportunity to focus and have an outlet of support for yourself.

Taking care of yourself is very important. It sounds so simple, but it is something that most of us have forgotten or forget to do in our relationships. The motto on the staying board is "before you can make anything better, you must stop making it worse." This motto has truly helped me improve my relationship with my bf. My journey of making things better started by focusing on myself and learning my role in the relationship. Take a look at this article.
Article 4: Take the First Step Toward Improving Your RelationshipIt is great that your partner is in therapy, self-aware, and is working on her maladaptive behaviors. What types of behavior are you having a problem coping with?