Hi titchsis,
I'd like to join
Learnnow and welcome you to the BPD Family

You most definitely are not alone in trying to negotiate a family member with BPD/BPD traits.
I can hear how much you love your sister and how hard you have tried to make things work with your sister, but that has involved a lot of "Walking on Eggshells" (there is a reason for the book title) and taking one for the team. (or many for the team)
It's really good that you can see the past dynamic has not been working and may actually have been detrimental to you. Once you see the problem then you can take it on, and make changes.
When your sister goes into a rage like the one right after your wedding, what is your response to it? What do you do?
I'm just so desperately sad for her and upset that no matter what I do I can't help fix her until she fixes herself.
That's it in a nutshell, who are the only people we truly control? That is ourselves none of us can make someone else do anything they don't want to do. That said you can change what
you do and that can have a ripple effect in terms of your interactions with your sister. This is where this site is really helpful, there are tools, approaches and information that I think you will find helpful.
I'm so glad you've found us.
Take Care,
Panda39