What do you suggest if my girlfriend has borderline personality disorder. help.?

Read a couple of: books to start: I Hate You Don't Leave Me and Walking on Eggshells. There are support groups for partners of BPD's. Check with your local United Way or go on the web. She might also seek treatment with someone who knows about this particular condition. It is difficult to treat and takes a while. Currently, we think DBT is the best Tx.

Borderline: The hardest thing to maintain with borderline personality disorder are interpersonal boundaries. Boundary violations often occur with people struggling with this disorder and whoever your girlfriend is, you're going to have to work on those boundary issues first and foremost, most notably in terms of safeguarding against being emotionally invaded or manipulated by that person.