My husband has BPD, and yes, being in a relationship with him and often being the brunt of his emotionally instability has taken its toll. But like your husband, I am dedicated to him and to our marriage and we have been together for 28 years. The effects of his behavior over the years has certainly changed me and I've required therapy specifically to work on how to counteract the effects of his actions and words on my life and my own mental health. Things have started to improve. My husband has started to make some gains in his own therapy and to make real changes in the way he approaches me. He's become more congnizant of how his critical words tear me down emotionally and works hard now to actively think before he acts, and it has helped.

Couples therapy was helpful, but perhaps if nothing else, he should see a therapist on his own to learn how to set good boundaries with you so it is clear to you when you have crossed the line. I used to let things go too far in my efforts to be understanding, but what I was really doing was enabling really poor behavior from him. Once I learned to express my own boundaries and hold them for my own well-being, my husband was better able to monitor and manage his own emotions and behaviors better.