
Welcome to this board. You'll find some great people here. And this board is a wonderful resource to search through looking for stories similar to yours. Brush up on your interwebz search skills and dive in! Continue to post and ask questions. There are many, like myself, that lurked for years absorbing the lessons from each story to help in my situation.
Have you read "Stop Walking on Eggshells" by Paul Mason and Randi Kreger? Some good background information on BPD behaviors you may find helpful. Splitting is highly recommended too. If there are BPD behaviors involved, it's a great resource for preparing for separating and divorcing. Do you have children together? If so, what are their ages?
It's encouraging to hear he's back into therapy, but true change takes years and a dedicated commitment to therapy (CBT or DBT). It's a long, hard road, but perhaps he can be one of the success stories.
Plan for the worst, hope for the best. Good luck. CoMo