Hiya!
Welcome.
You can find support here. There are heaps of people here who share experiences as partners of persons with BPD.
... .I was with my bf for three years, he appears to have many of the traits of BPD and perhaps depression.
Could you share more about the BPD traits and the depression?
He would get so defensive over the smallest things, but he would have no problem saying those exact same things to me.
Sometimes when we say one thing as the speaker, we don't have it within us to empathise by putting ourselves in the listeners shoes.
one day he snapped at work and broke his hand, and things quickly went down hill from there. I wouldn't hear from him for a week and he would say he needed a mental break, which i could believe his last day off was 8 months ago, and he literally works 7 days a week 12-14 hour days, its his business, and he has another business, and he helps his parents out, so he has an insane amount of stress.
I know that's a lot of things causing his stress. Trying to do this many things when we haven't got the capacity to do so can keep as at very unhealthy levels of stress.
Where are you at right now?

I look forward to hearing more of your story.