I'm sorry for what brought you here but I'm glad you're with us. We help and support each other here. From what you have said I think you belong here; you will fit in; your situation is like a lot of the other members. You will see from reading the posts here that you are far from alone. There is a lot of venting that goes on here.
I'm pretty sure that we have all said some things that were hurtful to our significant other; I know that I did! Even when I was trying not to say hurtful things, they came across that way to my uBPDexgf. There is a lot of information here - articles, workshops, etc. - and we'll help you find what you need to avoid doing things like that in the future. There are communication skills that will minimize the behavior of someone with BPD and these have proven successful for some of the members here.
If I might suggest, there are some great links to the right of the page that will help you get started.