I should acknowledge that she is actually exhausted. I should ask her to help in a compassionate manner.
Yes exactly. S.E.T. is for communiciating issues in an understanding and empathetic way, so that the situation is less likely to escalate.
I guess I just need to realize that she will never be everything I want.
I think this is an important realization for every relationship not just BPD. Nobody is able to always accomodate their partners needs. People change. Relationship dynamics change. And once the honeymoon phase is over new issues may arise and we may need to adjust our expectations. Accepting our partner as he or she is right now can release a lot of pressure for both sides. This doesn't mean you have to let go of your needs and wishes. But it does mean that they are only achievable in cooperation wit your partner. And since our partner has their own needs and wishes - which may not be in line with ours - we often have to find a compromise. This is why honest and respectful communication is so important. Redefining your expectations and treading a new path together can be a great opportunity to grow as a person and as couple.
Is there any way this SET can help me reduce her need to self harm? Or help keep her from getting upset and isolating herself?
S.E.T. is not the right tool for that. Self harm is a disfunctional behavior used to regulate negative emotions, to release pressure. This is something that is better adressed in therapy, where she can learn skills to handle her emotions differently and release pressure in a less harmful way. What you can do is listen with empathy by trying to put yourself in her shoes. Try to understand what she is feeling, how her reality looks like. Having somebody who really listens without judging or accusations can be very relieving in itself.
You could take a look at this page for a deeper understanding of empathetic listening
https://bpdfamily.com/content/listen-with-empathy. Especially the empathy skills could be helpful.
Feel free to share your thoughts!