Hi there. There are some tips near the end of 'I hate you - Don't leave me'. I'd also reccomend reading Linehan's book on BPD. If the person with BPD does Linehan's treatment program and their partner follows along with the stuff then there are lots of things in there about how to deal with SI and expression of emotion, distress tolerance skills, interpersonal effectiveness skills etc.

Stuff about healthy ways to communicate (which can be used by both parties). Weighing pros and cons in terms of disputes / figuring how to comprimise and setting appropriate boundaries and so forth.