Thank you, teapay.
I'm going a new therapist this week, and hopeful he can help me develop some skills. I want to model mindfulness in my interactions with my BP wife for my kids.
I will look into family counseling, but I doubt my wife will support that effort. She's not been diagnosed.
In general she is very competent in caring for the kids. She is strict, but never physically abusive. The biggest issue I see is that she can be very harsh when disciplining / scolding the kids. It's a form of shaming that cuts to the core. "I can't believe a 10 year-old would leave their toys in such a

$# mess!." (Which, of course, is a ridiculous statement.)
She also is very reactive. She can go from zero to complete outrage in less than a second. The kids then scramble to clean up, and make mom happy. They want her to be happy and feel responsible when she gets mad. I try to talk to them about mom and let them know that she's mad about something else and that they can't make her happy.
The tricky part comes when she says to me, "It feels like your not backing me up," which is true. How can I validate the invalid outrage against my children? She also believes the parent should be the authority, so any questioning is viewed as a serious challenge to her authority.
I have not contemplated separation, but know I need to start thinking about it. To stay in it I could probably develop the skills to manage my side of our relationship (e.g., validation), but I think that's too much to expect for my kids.