Welcome, former lurker. I too lurked, I think most do at first. I had only learned of BPD for a couple months when I found this peer support community and only posted after I'd already separated and was soon to divorce. You're not the first to walk this troubled path and not the last either.
I'm not sure which book you're referring to, but I did discover one book written in the 1980s which had this observation:
And for the children to see this discord all the time isn't good for them even if it's not directed at them. Children learn by example. If this dysfunctional example is their home life growing up, what life choices will they make seeking relationships when they're grown and gone?
Living in a calm and stable home, even if only for part of their lives, will give the children a better example of normalcy for their own future relationships. Nearly 30 years ago the book Solomon's Children - Exploding the Myths of Divorce had an interesting observation on page 195 by one participant, As the saying goes, "I'd rather come from a broken home than live in one."
Ponder that. Taking action will enable your lives, or at least a part of your lives, to be spent be in a calm, stable environment — your home, wherever that is — away from the blaming, emotional distortions, pressuring demands and manipulations, unpredictable ever-looming rages and outright chaos.
It is good you and your spouse are getting therapy and meds (though meds are not a complete solution) but the reality is that at some point the priority has to shift to what's best for the children.