How do you know if it's just their bpd or if they actually don't want to be with you anymore?
The long-distance aspect is so tough- I was just in an one year long distance relationship so I can fully relate (we got married though- yay!).
Your question is super tough to answer and honestly, there might not be a real answer due to how the BPD mind works. For example, both my BPD daughter and BPD ex-wife can start a conversation with me over <whatever>, and ten seconds later they're staring out the window ignoring me. Five minutes after that, they could be mad at me for not finishing the conversation about <whatever>, even though they drifted off and eventually changed the subject.
Then I'd add fuel to the fire by defending myself, which could be met with a laugh or an explosion of anger. It's really a tossup which one I get because it's based on their emotional state in real time.
If your person is pulling away, it could be one of a million things going on...most of which have nothing at all to do with you.
- It could be guilt and shame....what if they found out what a mess I am?
- It could be coping mechanisms...I'll just do my favorite stuff until I feel better.
- It could be suspicion...do they actually want to be with me? Am I wasting my time?
- It could be their inner circle, which is often others with similar mental health issues. These questionable friends are highly trusted because they understand what it's like to go through stuff, so they can go through stuff together and feed off one another's drama. These are often highly toxic relationships.
If your partner says they want to continue the relationship, then I'd trust that (for now). But I'd also want to find ways to improve communication and being the one he reaches out to when things are challenging. The more he feels like you're there for him without any judgement, then the more he'll open up and let you in.
And PS, I'm not saying that you're not already doing that. With BPD in the mix, you have to be even more transparent with your feelings and emotions when something feels off.