I have been living separately from my BPD husband for close to three years now due to me not being able to handle his instability.
The goal was to slowly move back together and reintegrate as a family (we have two young children), while he worked on self-regulation. He has been attending individual therapy for at least two years, and has completed two rounds of group DBT therapy. Some of his problem behaviours that made me feel unsafe are random bouts of screaming, slamming doors, dissociating (his eyes become glazed over and it looks like he is "not there"). He can get a job, but inevitably quits the job when triggered and also goes on out of control spending sprees. He is unreliable - when calm, he is sweet, caring, take-charge, and is responsible, but when triggered, he does not fulfill any responsibilities or commitments. He ruins most holidays, vacations family outings etc. by having some sort of tantrum. He has a major problem with emailing and texting in a completely out of control manner, and sometimes sends these rants to my parents and siblings, which is highly embarrassing.
Despite him consistently going for therapy, and demonstrating more insight into himself and his past, he has never taken real ownership of his issues. Sometimes I wonder what he is actually talking about in therapy. He will say sorry after "losing it" and "I have a lot of work to do," but at the same time he does not show true accountability. He has told me many times that he knows he has a problem and that he is aggressive and that he has mental health problems, but he very often says "it's not my fault" or gives the impression that he is a victim of circumstances. Or he will say that it is mostly his fault, but only if it's also a little bit my fault

. It's almost like his life goal is that things should not be his fault. I have never even used this language of "fault" at all - I would have liked if we could see it as a couples' project of helping him improve his mental health and therefore our relationship, but somehow he always brings it back to this language of whose fault it is.
Even after three years of trying to get our family back together, he always ends up behaving in a way that prevents us from moving forward - hard to tell if this is subconscious sabotage or not. As of late, he had been able to go longer before losing it, but inevitably the crash came again. Also, although he will say he understands that I moved out because I did not feel safe, at the same time he constantly accuses me of stealing the kids and of living separately from him. Which obviously makes no logical sense. It's very confusing - he seems to want to work on himself so we can live together, and at the same time, he never holds it together so we can move forward.
Over time, I have created more and more boundaries in order to be able to feel emotionally stable myself and be a healthy mother for my children. Some of my boundaries are - I will not communicate with him via texting or email at all ever, given his angry rants in these domains. If he screams over the phone, I hang up, or if in person, I leave. I also never depend on him for anything - if calm, I am happy for him to help out, but otherwise I am happy to do everything myself. I never leave him alone with the kids, as I am concerned about what would happen if he was triggered and started dissociating. Until this past fall, he was participating in our lives when calm and when dysregulated I just basically shut him out in the ways I described above. I have tried validating techniques, but somehow, they don't work for him or calm him down. It's almost like he needs the release in order to go on with life. So at this point, I've given up on that.
In the fall, there was a big shift. He had the longest streak of self-regulation that he had ever had, about 6 weeks, and I could see that he was really trying. Not to say he wasn't having challenges even within this period, but it was the best he ever was, and I felt hopeful. After this, he became triggered by something and crashed very badly, and basically said I have to move back home with him and refused to engage further. I was so disappointed when he lost it after the 6 weeks, and also I could foresee that his silence would likely last a while (he can go into silent/avoidant mode when very stressed). So I decided for the first time to just leave him be and not try to help him recover or rescue him. I figured it is his chance to take accountability if he is capable of doing so, without me pushing it on him. After a couple weeks of silence, he started sending physical letters, and has been doing this for months. I won't go into the specifics of what is in them, but they are mostly what I call fantasy based. He talks about how he is renovating our place so it will be nice for the kids (he seems to have "forgotten" they don't live there), tells the kids he misses them as though he is in a far away land etc. He has not once taken accountably or said he is sorry or addressed any serious issue. He talks about random businesses he is starting (fantasy) etc.
When he initially went silent, I decided that I was not going to respond to anything that was "nonsense" or fantasy. Since there was nothing real to respond to, there has been no back and forth communication for around 4 months now, during which time he has not seen the kids or asked to see them. Recently, I got a letter from him saying that he wanted to visit with them. This was the first real communication I have gotten from him that is not in the nonsense or fantasy category. I'm worried about reopening the cycle again, as he has not taken accountability or shown any insight into anything since he went silent months ago. It has been kind of shocking to me honestly how long his fantasy letters have lasted, without my intervention. I guess I was subconsciously doing an experiment to see how he behaves when left alone, and it is not pretty.
I'm not sure what exactly I am asking from this forum, and maybe this is just me having the opportunity to express what I've been through. I have so many conflicting emotions - while I am frustrated and upset at him, I also feel really bad for him that he is this "damaged", for lack of a better word. And I can see it more clearly now that I have left him alone and been totally disengaged in his cycles while observing from a safe distance. I did respond to his request about visiting with the kids (the first letter I replied to given that it was the first "normal" thing he said) and told him I will think about what makes sense and is in their best interests. This was done in a voicemail, as he did not answer the phone, and I am guessing he is too scared to do so. Does anyone have any thoughts on what would be in their best interests? I would love for them to have a healthy relationship with their father - that was my intention the whole time in separating from my husband - but I am scared of letting him back in to our lives given that I don't see any real change in him over the past months. I guess I was really wishing and hoping that if I left him alone, maybe he would show more capacity than he has done until now. And yes, I know that this almost certainly triggered his sense of abandonment, but somehow you can never win with BPD - engagement in the cycle doesn't work and disengagement doesn't work either.