Seeking an honest opinion from those with BPD. 

I’ve dated someone with BPD and every time it feels like we get close to place where we might be able to move forward concretely with a relationship she runs away. She will tell me how much she loves me and how she doesn’t want to do this life without me, but then her behavior is the opposite. She ghosts then starts dating someone else posting pictures with them on IG and 8 months will go by. Then a few weeks after her breakup, she reaches out and pretends like she didn’t know 8 months went by. 

I struggle to understand why she would say these thing, but then doesn’t follow through. I guess I’m just trying to understand why she says one thing, but then gives the life we could have to others who she claims she didn’t have feelings for. Why not just walk away and leave the door closed? Why keep coming back to restart things and then run away again and again ?

Maybe I’m just an idiot. Either way, could use your comments