Smileypants, I am so sorry to hear about this.
I have a uBPD/uNPD H and what you are seeing is very common in BPD men.
My H is also very high functioning with a very important job. He also dysregulates over the smallest things, including food: dinner not done on time, my making a chicken dish when he was expecting beef, etc. Early in our marriage, he exploded when I ate a leftover sandwich that he was planning on eating. I mean, literally exploded: rage, getting in my face (like drill sergeant), slamming his fists on walls, etc. He has punched holes in walls and doors, torn light fixtures out of ceilings, torn telephone cords out of walls (which is illegal), and stabbed knives into kitchen cutting boards.
A person who is BPD in the house can create havoc. Ironically, or maybe not surprisingly, he is never this was with his own children. In face, while they were growing up, he was as submissive as a doormat with them. They walked all over him and he gave then everything they wanted. He was seriously enmeshed, especially with the girls. It's good his family is supporting you, but don't count on all of their support once the divorce settlement comes to bear. Wrong or right, he is still their family member and they might protect him in the long run. (His children always support him over me as they want his money.)
I agree that your safety and the safety of the children is paramount.
In the meantime, do not disclose your plans to him. Keep them secret.
Also, this is a very good guide book for those divorcing an NPD or BPD spouse:
https://www.amazon.com/Splitting-Protecting-Borderline-Narcissistic-Personality/dp/1608820254Be well and be strong. Being married to a BPD is crazy-making.