Hi,
I've been with my soon to be ex-wife for 17 years. She's always suffered from anxiety and migraines, as well as on and off depression. 3 years ago she was diagnosed with ADHD (shortly after our older child was). She has always pushed down her own needs and feelings to do what she thinks others expect of her (even though she is very often very wrong about those perceived and imagined expectations). There have never been any major outbursts or outwardly impulsive behaviors, but that is because she turns it all inwards. The exception being somewhat routine "panic attacks" where she would always tell me that I was going to leave her, that i wanted to leave her. Sometimes as part of these I learned she would cut her hands superficially. She has been in and out of talk therapy for the entire time i have known her, never to much effect.
2 years ago she started EMDR therapy to work on her pushing things down and to learn to ask for the things she needs. This is around the time that I returned full time to a demanding job after years due to a series of family needs (newborn, COVID, health issues). As my attention was less on her, the testing and black and white thinking increased. Her weekly therapy left her with 2-day long emotional hangovers. Her sensory overwhelm was always in the red. Despite working 65-70h weeks now, I had to constantly step in when she was parenting, send her to relax and to take some time to herself. Did I mention we also had a puppy at this time

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The EMDR worked in that she finally felt OK asking for things, but she wanted me to change. To modulate my personality. To mask. And to mind read and step in at exactly the right times to tell her she was a good person, even though she is so skilled at masking there is no way to tell.
All of this finally broke me and I started to withdraw more as I reverted to my own maladaptive responses, which only accelerated to things. Finally in January she told me she was thinking of separation, but that even if we started couple's therapy that she thought she had too much resentment for it to work. She was right. I did my best, but a switch had been flipped and now every work and action was seen through dark glasses. Before she would misinterpret every work and sigh as a criticism of HER. Now it was all about me being wrong.
We are now going through divorce proceedings (collaboratively, no litigation). However my older son has very high-impact ADHD (like her), and exhibits frequent rejection sensitivity and black and white thinking. I am afraid for the impact the divorce could have on him. Unlike her, he does act outwardly rather than inwardly when he acts out, so if his BPD traits were to intensify, he would probably not exhibit "quiet" BPD as she did.
About 4 weeks ago a friend of mine told me to look up quiet BPD and it was like finally having a map! However given that my wife is undiagnosed and split negatively on me, I cannot bring this up. Were it not for our children, I wouldn't feel the need to ever raise it. However, I need to make sure my son gets DBT therapy. I also would like for her to not have unhealthy relationships in the future so that my kids see healthy relationships modelled on both sides of the custody (middle school and elementary school).
Does anyone have any advice on how to handle this situation? Do I advocate for DBT for my son simply out of its value vs. HIS black and white thinking? Do I mention possible BPD to the psychotherapist / counselor working with us (without telling my wife)? Do I wait 2 years until she is less split black on me and then tell her?
My gut tells me that the order I put those in goes from good to worse... but perspectives are welcome.