How do you think I should handle this...How can I chose. I get why he called the police. I told him no but he did it...
Hello and welcome to the family! I'm so sorry you're going through this and there's a lot for you to unpack.
First off, it is commendable for you to say that you were a part of the problem- that's true in all BPD relationships. We can choose to be supportive or to give into moments of anger, and it's almost impossible not to make some mistakes. It's a mature viewpoint that you had a role to play in how things fell apart.
With that said, physical violence is never the correct answer...whether you were a lousy boyfriend or not. You were wrong AND she was also wrong, so don't take unfair blame here. Hitting a driver while on the highway is never acceptable and the restraining order was warranted.
It sounds like you're already talking and she gave you an ultimatum- her or your brother?
That's classic manipulation and here's the problem with that; if you cut your brother out of your life for looking out for your best interests, then what happens when she gets mad at your mom, your dad, your boss, your in-laws, etc? How many people are you willing to cut out from your inner circle just to appease a possible love interest?
Please hear me here...your brother did the right thing to protect you. If there was violence and a knife involved, you could have been killed. If you were my brother, I'm making that call 100 times out of 100 and not thinking twice about it.
So before you restart this relationship, it feels like you have to call her bluff and have her hold as much accountability as you're holding. You were a lousy boyfriend at times. But she crossed a line that could have led to life in prison. Those are not two equal things and she was wrong. If she can't own up to that, then it's going to be very hard to have a real relationship.
Because think about it, It's July 4th and your parents are having a BBQ. Or it's Thanksgiving, Christmas, whatever. Should you tell your parents that your brother can't be there to appease your girlfriend? Or do you isolate from your entire family to make her happy? That's not a relationship, my friend, and this will happen many times per year from here on out.