Hi there, Jenny

Welcome!
Your post shows great self-awareness and steadiness. It's typical that only the ones closest to the pwBPD will know just how difficult relations can be. This can be another factor that makes these relationships very lonely places to be.
You are right that the only one you can help here is yourself. Having a better understanding of the condition and some tools to deal with communication difficulties will be useful for sure.
Please check the banner here on the right to start, if you haven't already. It has a lot of great information.
Are your children all quite young? How do you feel the parenting from your husband is? Have you friends or family that you rely on in any way? How are you coping in general? Is there anything specific you might like members to engage with first?
Look forward to hearing more from you, take care