CC and Pook,  I appreciate you both very much.
CC, I tried your Mantra "It's not time to worry yet".  I needed to contact my son about my grandson and I could feel myself getting anxious about my son's possible mood. Your Mantra did help. I since have fine tuned it for my over active imagination. "I have "no reason" to worry - so I won't.   
Pook, boy - you hit the nail on the head. Each time  you wrote "its not your fault" I felt myself choked up.  As I've learned more about bpd - I have been able to let go of carrying all the blame. Especially hearing for so many years how I am to blame. I understand his words at that moment are bpd speaking.  I happen to be blessed that my son can also speak kindly to me. That piece of fault I carry is looking at how I missed it, how I didn't protect him when my intention was to. Lots of thoughts can haunt me. I guess the answer is not to look back and judge myself. To even consider he may have this illness even if I did everything right.

In reading over the following, it is very long. I do not have family to help and I cannot expect friends to understand.
I have recently been living with my 43 year old daughter in her Housing Commission Home. This has occurred due to financial strain in both our lives. This morning, I walked past her bedroom and said good morning and she replied in a tone that suggested she was far from ok. When I asked what was wrong, she replied, in a dark tone, not to worry about it! Hence, I walk on eggshells and succumb to a sense of what might happen next.
I then decided to look on line for ways to cope with a child with BPD and found this site. Reading what everyone has said resonated.
My daughter was born with some physical disabilities and had a few operations in her early life. She struggled academically, but more importantly, making and keeping friends. People constantly disappointed her or did not agree with her ideas. Her adolescence was difficult. Her father left when she was just 14. She had adored him and this left a big hole in her life. He dismisses her behaviours as my bad parenting and says he cannot deal with neurodivergent people. He has, over the last 30 or so years, made some effort to have her stay with him and his various partners. When she threatened to set his house on fire, he gave up. Understandable, I suppose.
When she was 4 she had been diagnosed with ADD and given Ritalin. This helped until she refused to take it.
When she was about 18 years old, a much older doctor diagnosed her with bipolar disorder and she was medicated. It was not that she had mood swings, but rather continuous negative behaviours and interactions with others. No one matches her expectations. Over the years I have read about BPD and can see that the traits are similar to those displayed by my daughter. She will not listen when I suggest seeing someone about a reevaluation of her condition.
Her sister and Brother live far from us. They spent years seeing her ruin family life, many times that should have been happy and fun, particularly birthdays and Christmas.
She had a relationship and had two children with this man. She left the relationship when the boys were 3 nd 5. She still has close contact with him. Their eldest son has Autism and extremely violent episodes. Both boys lived with their father and the younger brother lived in fear from 8 until 14 years old. The eldest was taken into care at this time and now lives in a community home with a carer on call. He is 20 this year.
There was a period of about a year when we lost contact. We had been living together. I was full-time teaching and she was home doing nothing! I tried to get her to help with the cleaning, washing, anything to get her motivated, but she lived in a mess. She also smokes, still smokes (despite the price of tobacco) and would not walk to the closest place to buy her cigarettes. I had to drive her. I know it sounds like I was pandering to her moods, but I did not want to create tension. I constantly walked on egg-shells at home. One day she hit me a couple of times over the head. Not to hard, but scary. I felt like I was in jail.
One evening, I had had some wine and gone to bed. She came to my room and demanded that I drive her to the shops for cigarettes. I explained that I had had wine and didn't want to lose my licence. She was angry and went out and came back with a knife. I managed to get dressed and take the dog and myself out. I called the police.
Last resort, but I had had it. They came while I was outside. She was holding a bag of peas to her face and said I had hit her. They took her to a psychiatric centre for assessment and I took out an AVO. I did not see her for a year until she needed help finding a place to live.
Family Support felt that her eldest son might benefit from living with his mother. While they waited for a home, they went from motel to motel. The son created havoc each time and they had to leave. One night at about 12am I received a phone call from my daughter. They had ended up at a police station near me and had been put out onto the street with nowhere to go.
I collected them and they stayed wth me for 6 weeks until a house was found.
The situation with them living together was difficult and my daughter was exposed to violent outbursts. The last, when he chased her into the street and attempted to strangle her. Luckily, neighbours helped and called the police.
My daughter lived on her own until before last Christmas when I moved in for the holidays. I had tried to help her over the 3 years she lived in the house alone, to look after her house (I lived and worked an hour away), coming down on weekends cleaning and cooking, spending. Her son's father is also close and mows her lawns and comes to see her.
She has created a relationship with someone she saw years ago. This person talks to her in her head. She does not see him.
She talks about being hit with a belt by her father - this did not happen.
She sits on the lounge all day, going to the kitchen for food, only to return to the couch.
She feels she has been bullied about her looks all her life (she does have a big nose, but so do I and her brother) and is using that as an excuse not to eat well, exercise or shower.
I am now in the position I was before. Cooking, picking up after her, staying out of her way when she is edgy and generally keeping things going.
I am not a saint. I've made huge mistakes financially and in choosing a new partner (my daughter ended up living with us, which was difficult). I didn't deal well when her father left and I know at that time I wasn't a good parent to my three children. But I'm trying to learn from all my mistakes and help my daughter find some positivity.
If you do read this, then thankyou.

How are things going

One quick piece of advice since I faced this often with my BPD daughter.

I would not validate the invalid.  So if she said, "You did this and that, which caused me to do this and that..."  Nope, I don't do that.  I won't respond to any of that stuff either because I'm not fighting the battle within her mind.

On the other hand, we can always validate feelings.  When I get those unhinged rants, I will quickly say (when I'm permitted between rants) that I never meant to hurt her feelings and I am so sorry that she's felt that way.

If it goes back to "You did this, and you did that..."  I'll just wait patiently for my turn to speak.  If I just can't do it, then I'll make up an excuse and hang up...but I try to hold out as long as possible.  Then I'll repeat the same statement.  "<daughter>, I never meant to hurt your feelings and I'm so sorry you're feeling this way."  If she's actually letting me talk and listening, I might add, "I would never do anything to actually hurt you, I love you so much."

That either cuts the tension or it doesn't, but it does offer a sincere apology (for feelings) without speaking a single word towards the accusations. 

I hope that helps!

After reading all your responses and reflecting, I realize that although my reaction to my daughter's pregnancy was natural, it was not well handled given that I know I'm dealing with a pwBPD. The email I sent was also pointless, I should have known it would be, and based on her reaction---it must struck a very deep nerve. Today I decided that I would try to rewind things sooner rather than later, and just reach out to her to tell her I love and that I'm here to support her. My decision to reach out to her before she circled back to me was based mostly on the fact that I saw on my Life360 app that although she went to school yesterday morning, she was back at her boyfriend's by 2pm, and that she wasn't in school today. When I tried to text her it appeared I was blocked, which was confirmed when I tried to call her from my cell phone. So I picked up the land line and called. She answered and was completely unhinged, clearly not wanting to "start over". She continued to spew the lie that I threatened to call CPS and take her baby (a complete fabrication), with the emotion of someone who actually believed it. Then she blamed that lie for making her "feel this way" and told me she was at home alone and had to take a week's leave of absence from school because due to my words and behavior toward her, she had been "all over the place". I can't be sure if the leave of absence was a decision she made for herself or if the school imposed it on her, but I don't think that a week alone all day is going to be helpful to her. Anyway, she was demanding that I apologize for things I never said, telling me I'd never hear from her again if I didn't, and was just crying and screaming. I am sort of taken back by all this whether I should be or not, because "usually" when she flips out, the dust settles relatively quickly and she stabilizes after the toxic emotional release. This is something else. I don't think I have any choice but to just leave her alone until she circles back to me in a non toxic way. I don't think there's anything more I can do or say in effort to try to help stabilize her short of apologizing for a complete fabrication, which I don't think is advisable. I also fear that any communication from me could destabilize her more. Please correct me if I'm wrong. I am so worried about her, the baby, the father, and his little girl. I'd be shocked to find out that my daughter's general behavior around him/his family hasn't changed dramatically for the worse and the pregnancy he was initially "excited" about is evolving into a destabilizing situation for everyone. I can only hope that's not the case.

Thank you all for sharing, really appreciate the insights and care!

Well it looks like your therapy training has given you some insight into your own situation.  The way I see things, your husband is getting worse because you have a young child, and as you wrote, your attention has been necessarily diverted towards the baby.  You see, pwBPD are triggered by feelings of abandonment and can get upset whenever 100% of your attention isn't on them, even if the reason is you're busy with his own baby!  I suspect there's a little regression going on too.  He sees the baby gets your attention when she fusses and cries, and he does the exact same thing.

On these boards I've seen references to pwBPD lacking "object constancy," the ability to maintain a stable, positive emotional connection with a person even when they are absent or when they feel angry/frustrated with them, understanding they are a whole person with both good and bad qualities.  For pwBPD,  object constancy seems to be a challenge, as their black-and-white thinking dominates.  So if you leave, or you're busy with something, or you're tending to your precious daughter, your husband assumes the worst.  He might think, you don't love him and don't pay enough attention to him anymore.  In short, you are not meeting his needs!  And by the way, it's all YOUR FAULT for making him feel this way.  I think that's what your husband means when he's hitting himself.  YOU are the one who unleashed these negative emotions inside him.  He has been displaced and upstaged by his own kid.  It's sad, but it sounds like inside he has the emotional maturity of about a toddler.  At the end of the day, he is extremely insecure, and he has unending emotional needs for your constant attention and reassurance.

In my opinion, if your husband is actually violent--bruising himself, threatening to use a knife--I think you need to call 911.  You used the word "violent," and that's why I'm writing this.  You have a young daughter to think about, it's a very small escalation to turn his aggressions onto her and you.  In my opinion, you need to have a firm boundary when it comes to violence, and call 911 straight away.  One would hope that one single call to 911 would teach your husband that violence isn't allowed in your home, and violence would be off the table.  If he doesn't learn, I think you have to seriously consider the safety of your daughter.

As for shouting and obscenities in the home, while it's certainly not ideal, it does happen, even in families without any mental illness.  In my opinion the rule for me would be, no shouting or obscenities in front of the children.  If he started a scene, I'd remind him of the rule, try to steer him outside or out of earshot, or possibly leave the scene with the child under my wing, maybe go for a walk, a drive, a trip to the library.  With some luck he'd have time to calm down during this "adult time out."

Well, welcome, and sorry you're going through this.  We all went through our own journeys of understanding and resolution in a way, whether the person in our life was our spouse, partner, BF/GF or a family member.  Even some who aren't directly in contact with the pwBPD post here, such is the nature of the disorder that it upsets entire families, and even affects new step-moms and step-dads who's current partner has an ex that is BPD.

I think it's important to stay calm and realize that your feelings and understanding are going to take time to form here, and are going to be influenced by not only what you read and learn, but what you continue to experience.

One thing to prioritize as you decide your path is your daughter's needs, safety, and development.  Whatever you decide to do, you have to make that decision understanding your obligation there as a parent.  And you have to understand that you're the only "adult" in the home capable of making these decisions for her.  You're basically on your own, when your partner has BPD; they are incapable of putting their own children's needs in front of their feelings and emotions in the moment. 

Good luck and I've found it's helpful to post here, and read other threads too, in that others' experiences can often inform our own and lead to other insights that help you recover. 

How did your husband handle his own diagnosis?

The biggest thing you have to remember- this isn't your fault.

And I know you probably understand that, but you actually have to KNOW IT as a fact and let it really sink in.  Absolutely none of this is your fault and you've done nothing wrong.  As parents, we do the best we can in challenging situations.  It rarely works out like we plan and we learn as we're doing it.  You weren't perfect because no parent is, but you continued to try and delivered everything you could.

So I'll say it again, this is not your fault.

Next, it's not 100% your son's fault either.  He knows there's mental illness but his viewpoint is so warped, he lashes out at those closest to him whenever he's in pain.  That's literally so common with BPD- the more they need you, the more you see the dysfunction and abusive behavior.  It's really sad and I want to help just as much as you do, but our version of help often becomes enablement.  That's why everything always backfires, the mental illness tells your son that you owe it to him for not being a better mom.

But I'll say again, this is not your fault.  You were not a bad mom.  He's sick and doesn't think clearly at times.

The sooner you accept this one fact, the sooner you can take a breath of relief and realize that it's time for you to heal.  That actually makes you a better parent because you'll gain more patience, more understanding, and more compassion.  But at the same time, your eyes will be opened to what's actually happening here.

I hope that helps.  One last time, this is not your fault.  You have to let that part go entirely.

Hi SuperDaddy,

I am sorry to hear that things have esscaleted so much that you have decided to move out. Are you planing to separate or staying a couple that does not live together? Do you wish your moving out will be a wake up call for your wife to start behaving better? I wish you all the best, as we talked before and in this threat, this could end up being a wake up call and boundaries might be enforced better. I see that you are naturally worrying about your wife‘s mental health if you move out, but please put the children and yoursef first, do what you have to do to protect yourself. Sometimes BPDs are able to take better care of themselves when they have to…