Hello fitdad and welcome to the group

So much of what you describe will sound familiar to other members here -- you are not alone in this. The blame, lack of support when a family member is ill, threats, trying to parent young children in the chaos... this is beyond difficult, and many members have been in your shoes.
While there aren't easy solutions, it is possible to make a relationship more livable for yourself beyond just "suck it up and be stoic". A lot of the potential for making your relationship more livable for you rests with choices you make (versus trying to make her do or not do things), and a big one is getting support for yourself. You mentioned trying counseling -- are you still going? If so, do you feel understood by your counselor?
Does your W work outside the house? Is your 3YO in daycare or out of the house yet? Just getting a picture of who is doing what and where.
There are a lot of moving parts to your situation, and I get the fears and wondering about "OK, if we have to divorce, will I ever see my kids again". Let's take it one step at a time -- that's certainly not an unimportant question, and yet getting yourself to an emotional baseline now can help you make some wiser choices for a path forward. It might look like staying together, if things can stabilize/get "livable enough"; it might look different; but all you can do is what you can do in the present moment. I do think I hear you wondering about staying together, so we can focus on that for now.
Thanks for listening, I guess I just needed to vent. How do you all deal with it? I've been advised that all you can really do is try and be stoic, but that's tough in the face of blatant disrespect, gaslighting and efforts to sabotage your ability to make money and survive.
The person in my life with BPD is my husband's kids' mom, and yes, it is hard to find people who understand how difficult BPD makes a family situation.
For many years, my H and I had a marriage counselor, and I currently have an individual counselor... even though I'm not the one with BPD, my H doesn't have BPD, and I was never married to the pwBPD. It's that pervasive in a family system. So the #1 way I've dealt with it is by getting professional support.
I also learned a lot about BPD and about why my preferred communication methods (of pointing out inconsistency, using charts/graphs/numbers/logic, and trying to "win the argument") were ineffective at best and counterproductive at worst. We have a great section of threads on
managing conflict that could be helpful in turning down the temperature in your home. Getting educated about BPD has helped me understand the reality that it is a serious and impairing mental illness, and me doubling down on how I wanted to approach conflict was not helping at all, and was making things worse.
For folks here on the "Bettering a Relationship" board, a new approach that can be helpful (that doesn't require the partner's cooperation!) is to
Stop Invalidating Others. If I could only recommend one tool to members, this would be it. And it's important in all relationships, too (parenting, for example), not just BPD relationships.
Take a look at some of those links and, when you have a moment, let us know what stood out to you, or seemed do-able, or resonated with your situation.
We'll be here;
kells76