The biggest thing with my (ex)BPD was a complete lack of boundaries. Infact if a boundary was agreed upon she would as quickly and efficiently as possible try and cross it. This would be done under the blanket of a you did this so Im doing this scenario which often was completely manufactured or at best over inflated.
Some classic examples right at the start of our relationship I went to a mates 40th, she calls me and I don't come immediately home so that gives her permission to call a ex and flirt with him. When I questioned how she can justify it her reply "I thought you were flirting with girls at the party".
Recently she invited my female neighbor over for drinks, got it in her head that I wanted to **** her "how long will it be after we break up will you **** her". I see where this is going and go to bed lock the bedroom door and leave her to sleep on the couch. She locks herself out of the house, goes over to my male neighbors place, drinks until the early hours of the morning and ends up sleeping in his bed. When questions how she can justify it? "You locked me out of the house I had no choice".
This is just a couple of examples but yeah the complete lack of boundaries and justification is probably my biggest issue.
