Hi Unknown User and

I want to share with you my experience with my ex BPD, and if you want, try to explain me the reason of this behavior.
I'll try to relate some of what you wrote to my understanding of people with borderline personality disorder (pwBPD). Hopefully some of what I write will be helpful to you.
I was together with this person for an year more or less, we move to live together in 2 months and at the third she start changing. After several arguments trough those year we broke up, and she moved out the day of my birthday this January.
Some pwBPD seem to experience a disordered fear of abandonment. And I describe it as "disordered" because they not only fear real abandonment, but also *imagined* abandonment. For some pwBPD, it seems that the more intimately connected to you they are, the more they will experience this imagined fear that you will abandon them. Such that even though you have no such intention, they will still feel that you will imminently abandon them.
As I see it, after you moved in together, as your BPD loved one's feelings of intimacy and familiarity started developing, she was probably also experiencing more and more this disordered fear that you would abandon her. For some pwBPD, these disordered feelings are highlighted on occasions of intimate and familial significance such as family holidays and special occasions such as birthdays.
* Once I got a call from a female friend that she was pregnant, she asked me I can collect her from the Hospital, so we can have a chat while I bring her to the bus stop. Be aware that she is engaged. My ex asked me if she can come over, and I just said that I preferred to see her by myself and that I'll come home in an hour, as I did.
She deleted her from FB, and said that I cared more about my friend then her. She always bring up this story in every argument by calling her "The pregnant princess"
When pwBPD experience this disordered fear of abandonment, they try to identify the cause of why they might be feeling this way. So any attention or assistance you might offer to a friend can become the lightning rod for their disordered feelings.
Your BPD loved one believed that you want to leave her, and when she saw that you were with your pregnant friend, she then believe that you intended to leave her in order to be with this friend.
* I needed to move back to my city for a week as my father was sick in the hospital and she got very upset by that.When I was there she was texting me very upset, by saying that I left her alone there. She didn't believe that I was at the Hospital, and she was calling the fact that I was at my city a "holiday"
For pwBPD, their imagined abandonment can happen not only because of imagined romantic connections but also from other close/familial connections. She probably believed that you would leave her in order to take care of your ill father. I believe that pwBPD can only be attached to one person at a time (even though this can change rapidly) and so it is difficult for them to imagine that we might be able to love both a family member and them at the same time.
* She always wanted to check my phone, but I never allowed her to do it as I thought that wasn't fair as I never ever thought to do the same thing with her mobile.
Because of their disordered feelings, I imagine it is nearly impossible for pwBPD to trust us. I don't think your BPD loved one was concerned about fairness; she was only concerned about avoiding her (imagined) abandonment.
* She was smoking weed every day, I tried to explain to her that I noticed a change when she start doing this and if she can try to do it only at the weekend.
She called me a control freak
Many pwBPD use alcohol, addictive substances (or behaviors) as a means of "managing" their disordered feelings. At the beginning of our relationships, when they were not so overwhelmed by their disordered feelings (because at that time, there will little or no real intimacy/familiarity), they had less to manage.
One Friday, early in the evening, she called me saying that she was very sick. I was worried for her and I asked if she wanted me to come over to her place to bring some food and medicines, but her answer was that she needed just to rest.
She called me at 2 in the night, saying that she was coming back home and asked if she can come over to my place. I didn't get upset with her for the fact that she lied, but I told here that she could come over.
ONCE she enter in the building she started insulting my friends (girls) out of nowhere, saying that I should f**k them, etc. She started getting quite violent, I tried to push her out of the door and at that point she punched me in the face.
The day after she texted me and called me several times to ask me sorry for what happen
Another way that pwBPD manage their disordered emotions is to use other people as backup plans. For example, if she was experiencing her fear of abandonment with whomever she was currently attached to: one way to mitigate that fear is to have someone else to whom she could run to and so abandoned her current attachment.
I imagine when she called you looking for attention, she was making sure that you could be a potential "recycle." And as long as you are receptive, she could leave whomever she was experiencing her fear of abandonment, and be with you. But when she actually came over to be with you, she found you with other people. And so her fear of abandonment got re-triggered all over again.
She always played with me the Hot & Cold treatment after the broke up.
I imagine because her "Hot" behavior always ended up triggering her disordered emotions which led to the "Cold" behaviors.
I hope some of this is helpful to you.
Best wishes,
Schwing