Hi Madbeacon,
Welcome aboard.
I am sorry that you are going through this. I understand how coping with accusations, walking on eggshells, and illogical behavior can be very frustrating.
There is hope. This site has wonderful resources to improve your relationship with your person with BPD (pwBPD). The motto on the staying board is, "before you can make anything better, you must stop making it worse." Having this mindset has improved many facets of my relationship.
The first way I learned to stop making it worse was learning about the behaviors of BPD. Having the knowledge to understand why my bf was acting in a certain way, alleviated a lot of my frustrations. Here is a link to get you started.
Article 2: The Symptoms and Diagnosis of Borderline Personality Disorder I found that having my own support system of my friends, family, and my therapist really helped me cope with many of my bf's behaviors. Do you have a support system?