The lack of sense of self I hear about isn't a trait my wife really exhibits on the whole... not any more than can happen with anyone. Suggestability probably runs with that, as it seems people are saying. In fact, she can even be kinda stubborn and seems to have more steady, set image of who she portrays her self to be. The problem is more along the lines of blindspots to where she is not that image.
But, I have seen things like this...
For example, once I gave her an idea for the business we owned and she looked me dead in the face and said that I was stupid. Ten minutes later one of her new favorite people came in and said you know you should blablbala (same thing I said) and she got all excited and said that's a GREAT idea can I come by your house later and we can talk about it.
...and generally chalk it up to splitting. If you idealize someone, their ideas are gold, so a pwBPD may respect and follow their suggestions more readily - even in cases where Joe says the same thing as Bob and Bob is shot down and Joe praised. It's a selective suggestability based at least on who and what status they hold in the BPD mind. With her, it's also selective/limited in scope... if Joe's suggestion clashes with her own opinion or something she's set on, nope. In fact, enough of those cases will drop Joe out of idealization as she realizes "he doesn't think like me, his ideas aren't compatible."
As we all are, she is more flexible on things she is more neutral on. Or, she will chameleon slightly as she gets along with someone, but there is usually limit to that and it is usually closer to what we all do to a degree. An exception to that is a guy who has become a bit of a problem in how his way of operating encourages and feeds into BPD problematically.
