LeeDeeBee, what a fun name you chose, first of all! I want to welcome you to bpdfamily.

We share so many of the same struggles and I'm confident that you'll find great support and guidance from the people here as well as the tools in the links above.
Congratulations on your engagement and how wise it is of you to look for support as you and your fiance build a life together. Several people here are in the same position. It's so important to start out on the right foot and set healthy boundaries to protect your relationship from the beginning, isn't it?

I'm more or less in your fiance's shoes and have a BPD MIL. It's been super challenging and has gotten worse over the years. I'm just thrilled that you've accepted your dad's behavior for what it is and you're ready to build something different for yourself.

You mentioned detaching with love and setting boundaries. Can you give us an example of how you want this to play out for you? Or we can work backwards from something that hasn't worked for you?
Again, welcome!
pj