Hi secondhand,
that sounds really like a big drama! IP addresses are a useful indicator where someone is coming from but ip location services are far from reliable. While pwBPD tend to warp reality a long term deception involving planning is not really typical. The truth will be hard to figure out if at all. Certainly not while emotions are running hot. Being deceived in such a way is certainly hugely upsetting. Being accused of such deception is certainly also hugely upsetting (and in this case upset is multiplied by BPD). Not an easy situation for anyone to handle!
Drama is common in BPD relationships as the b/w thinking and acting tends to feed it. Communication quickly breaks down. You feel you are in the middle of the two and have to control the situation. You can't and if you try chances are you just make it worse. Read up on the
Karpman triangle.

,
a0