I have BPD.
I have had an emotionally abusive relationship and several 'dodgy' ones.
I'm crappy with friendships, I am hot & cold with my parents - my DM is either hero worshipped or I am very sensitive to every.little.thing she says.
I think when you are really poorly (i see my BPD a little like bipolar, i definitely have cycles & times when I am much worse than others) then you do tend to pick the wrong parenter, well I do. I think the anxiety and the texting sounds a bit like BPD stuff, and as is the intense emotions - like feeling 'in love' after a month.
I don't think you are 'to blame' though. I firmly think adults who choose to smoke pots are pretty much all nobs, so maybe you are well rid?
Don't blame yourself for this, it won't help - instead learn from it.
I found DBT really useful in curbing some of my BPD attachment issue, but it is case of being aware of my emotions, my mood patterns and my tendancies.
I hope that when (if) you are diagnosed you can get help to stem these behaviours.
FWIW I have now been engaged for over a year to a lovely, kind, loyal DP who doesn't abuse me/do drugs/is a manchild - so there is hope. He helps me realise me when I am being BPD & we work together. so there is hope.
I'm sorry you have been through so much pain with this relationship though, i remember well the sheer hell of it.