It is hard to find our way through those moments when we are being buried under a landslide of apparent illogical nonsense.
Learning how not to react and be swept into the whirlwind, and ultimately feeding it is hard to do. We want to defend ourselves, but you cant fight head to head with a person with BPD and expect a negotiated resolution. That train is heading over the cliff. Try to stand in front and stop it and you will get run over, climb aboard and you go with it. Knowing when to step aside and let it go is the key.
This is not the same as being a doormat. When you learn about boundaries you will better understand this.
There is a lot of good information here to help you come to terms with this. You may not be able to reverse it, but hopefully you can stop the bleeding.
Waverider