Hi AlphaClare.
I'd like to join Maxen and Rapt Reader to our not so little family!
Not up to speed with all those emoticons offered to me - have enough emotion here at home, don't need to add symbols of it.

You made me laugh! How wonderful and encouraging that you are keeping your sense of humor amidst the pain and heartache you've been dealing with over your DD. (In case you change your mind, all you have to do is mouse click on the emoticon you want and it inserts the code for it right into the post. It took me a while to figure out that you can't see the actual emoticon until AFTER you hit the "Post" button.)
My DD is 17 and was recently diagnosed with BPD after a severe cutting event landed her in the mental hospital for a 3-day hold. So I understand the fear, the pain, confusion and frustration you've been living with. When I first came to this site, I was exhausted and in despair because I didn't know what to do and I felt so alone. The resources and support here are wonderful! I'm so glad you found us.
I want to normalise her state and say it isn't her fault, just a product of a conflict-laden home life (being simplistic to make it not her fault). I want to be open with her about how she could get help and live more normally if she could try some medication/ anxiety-relieving lifestyle changes, and learn some tools for moderating her outbursts. What do you think of my idea?
Your heart is in a great place! And I think you're ahead of the game because you have already been validating your DD's feelings. She might be much worse off than she is if you hadn't developed those skills as a social worker. I think I would read the links Maxen and Rapt Reader already gave you
before you talk to her though. Why re-invent the wheel? There are already tools and resources that have been found to work. Why not give them a try? I can tell you're a very loving mom since you're so willing to take some responsibility for your DD's pain. That's a HUGE step toward healing. I don't think you "caused her anxious tendencies" though. Marital conflict by itself does not cause BPD in children, or we'd all have the disorder. I'll bet, if you look back at her life, the anxious tendencies were always present. My own DD exhibited signs of anxiety (nail biting and picking at small wounds) when she started Kindergarten, only I didn't realize that's what it was until school was out and I had to trim her nails for the first time in a year and the scratches and bug bites finally healed. Since that time, my DD has had anxiety and stress from situations and events that would not cause distress for someone less sensitive. Has your DD always had trouble dealing with stress? Does it seem like there is always some kind of stress in her life?
Please tell us how your conversation goes! I'm so glad you joined us!