How do I know when to leave for the kids' sake?

[Protectourfamily]

My husband has (unofficially diagnosed) BPD, possibly as a result of an abusive and traumatic childhood. We have a bunch of kids, and our life is fraught with constant emotional ups and downs. It's like living on the spout of a volcano. It can be calm for hours, days, sometimes even weeks ... and then Boom!
I have become so much better at defusing conflict when it happens, but it does happen, and my kids (from toddler to teen) get shaken up when it comes. He can be borderline abusive, full of rage. My kids are having trouble socially and academically (how would you like to study math or play a board game as lava starts spewing?).
We all love my husband very much and know that he loves us. He is in therapy and on medication but it has only helped so much. His psychiatrist and therapist say there is nothing further that meds or therapy can offer him re: parenting/marriage.
When do I give up? I would keep trying forever, but my kids are on shaky ground.

[PLEASE - NO RUN MESSAGES]

PLEASE - NO RUN MESSAGES This is a high level discussion board for solving ongoing, day-to-day relationship conflicts. Members may appear frustrated but they are here for constructive solutions to problems. This is not a place for relationship "stay" or "leave" discussions. Please read the specific guidelines for this group.

[PeteWitsend]

I struggled with this as well.  And I was really concerned with the fact that if I left, I wouldn't be there for my daughter.

But as she got older, I saw I couldn't keep my BPDw (now ex-wife) from fighting.  and I saw the fighting was affecting my D negatively.

I also considered that by staying in a toxic relationship, I was sending a message that it's acceptable to be treated this way by your partner.  I didn't want to do that.  I didn't want her to marry a guy that treated her like BPDxw treated me and my extended family.

The information that factored into my decision was also that I couldn't be a role model of stable adult behavior while I was with BPDxw, and while losing time with my daughter was less-than-ideal, it was better than exposing her to fighting 100% of the time.

At least when she was with me, we could have calm.  As the saying goes, "I'd rather come from a broken home than live in one."

I had (and still have) concerns that BPDxw is bad mouthing me and trying to alienate my daughter from me.  I have to stay vigilant against that.  Also, I had some concerns BPDxw would make really unhinged allegations of abuse against me.  Fortunately that has not been something that has happened but there are horror stories on this site.

Unfortunately, with emotional abuse, unlike with physical abuse or infidelity, there's not as much of a clear cut line on which you can say "The benefits of leaving outweigh the harm of staying."  You have to make your own decision, and you have to stay vigilant afterward b/c you have children with an emotionally unstable person, so they have a lot of opportunities to continue to cause grief for you.