magic78 
Can people with BPD be genuinely sorry but unable to change their behaviour?
I think yes. My ex was repeatedly doing things that she was sorry for. Many things she wasn't sorry for.
I think for behavioural change, with many people it's a big challenge. A bit like trying to lift a tennis ball with chopsticks. For managing a BP—it felt like a trying to lift a beach ball. Can be done—but why would you do it?
Consider a lighthouse. It stands on the shore with its beckoning light, guiding ships safely into the harbor. The lighthouse can’t uproot itself, wade out into the water, grab the ship by the stern, and say, “Listen, you fool! If you stay on this path, you may break up on the rocks!”
No, the ship has some responsibility for its own destiny. It can choose to be guided by the lighthouse. Or it can go its own way. The lighthouse is not responsible for the ship’s decisions. All it can do is be the best lighthouse it knows how to be.
Source.
So then we see we want someone to change. I think to some degree that's pretty normal. People want their friends to change, their fellow workers to change, their spouses to change. "I wish my friend/boss/wife did X." Then we look inward, do we as SO's have an
abnormal want to change someone. If so—why?
I agree with some of the other members here.
Working through using chopsticks with a T makes things way easier.
You'll want to take the lead, like your role as emotional caretaker, to bring yourself through the breakup (wherever you're at with her) to a place you want the relationship to be. That also includes no relationship too—e.g., I wouldn't want to start a family with someone who's in bed with someone else.
You'll want to focus on results rather than the doing. 7 years and 30 breakups is what happened, it's also a result. Personally, I had 1.5 years and 40++ breakups. Thank our stars this isn't a contest—but focus on the numbers for a minute here. If the market you're measuring says 0–2 breakups is 'normal' for a long lasting relationship, why are you breaking up 30 times? Whatever you were doing together was causing that result, so why keep sticking it out? You can see it's a bit like being at the roulette table—"This has got to work in my favour, logically,
eventually!" BP relationships don't work like this.
Enjoy your weekend.