Hi StayingSane78

I see you haven't had any replies yet, so sorry about that! Sometimes posts fall through the crack for no reason. I'm glad you found your way here to us You have a lot going on in your life.
How does one do it ... It's not the easiest, that's true. I'm glad you have and enforce boundaries. We have
Setting Boundaries and Setting Limits in case you want some support in that.
There are success stories, though they tend to stop posting here as they don't need the support anymore. We talk a lot about tools like boundaries, and validation, and communication techniques and radical acceptation and all that. Though it all I think the most important is to have some outside support, though. Someone who truly understands what you're going through, and we do.
How old are you boys? You say they notice your husband's behaviour and naturally you worry about that. I don't have kids myself, but there are many parents here with partners with BPD. I hope you stick around, for support and help.
Warmly
Scarlet