How do even have a relationship with a BPD

[bear51]

I think that my Mom has BPD. I am not seeking to diagnose her... .I guess I am trying to figure out how not to let her extreme swings affect me. Before it was these huge emotional rages and now it is harder, it is cunning and manipulative behaviours. It is so hard to have an semblance of a relationship with her. You think things are going alone super well and then BAM you are blindsided about sided about something you did 3 or 4 weeks ago. I am accused of being defensive, too sensitive, or unable to accept constructive criticism. I am accused of not sharing anything with her and yet when I do it is used against me.
It is just so hard and so painful. The hardest thing is that I am missing out on a relationship with my Dad. I am just so tired of feeling like ___ every time Im around her but then told that she will always be the bad guy and so it is your own fault that you feel like ___. Im tired of fighting for a relationship with her.

[Naughty Nibbler]

Welcome Bear51:   

I'm sorry to hear about the situation with your mom.  You don't need a diagnosis to improve things for you, as you don't have the power to change your mom.  What you can change is the way you interact with her and react to her.  What is keeping you from having a relationship with your dad?  Is it that you want to limit contact with your mom?  Is your dad co-dependent and perhaps enabling your mom's behavior?

I am accused of not sharing anything with her and yet when I do it is used against me. It is just so hard and so painful. The hardest thing is that I am missing out on a relationship with my Dad.

Setting BOUNDARIES with your mom can be helpful for you.  Sounds like you are tried some already, by limiting what you share with your mom.  Boundaries are for you, and they aren't usually something a person with BPD (pwBPD) will agree with. 

Blame and criticism are sometimes things you may just have to set boundaries about.  You may just need to radically accept that your mom will do these two things.  If you set boundaries to not engage with her and walk away, politely terminate a phone conversation, etc., your can limit your exposure.

A good place to start with learning some skills/tools is to check out the "Tools" menu within the large green band at the top of this page.  Validation/Don't Invalidate is a good skill to master.  The link below to "Avoiding Circular Arguments" is, also, a good tool.

STOP CIRCULAR ARGUMENTS - DON'T JADE (JUSTIFY, ARUGE OR DEFEND)
https://bpdfamily.com/message_board/index.php?topic=118892.0;all