Truthfully, it could be anything and it's hard not to take personally. My ex is diagnosed with anxiety and depression. I feel that she also has traits of BPD.
Someone with BPD feels that their feelings are worthless and don't matter and underneath that can translate to:
therefore, I'm worthless, don't matter and an unworthy of being loved. The unintentional invalidation that we can do is a huge trigger. Hence, the validation tools which can help reduce conflict. I saw it with my ex today. She had to go for a short hike and run to deflate from being with the kids this afternoon. That's what helps her cope: release by exercise. She long ago refused meds her therapist suggested. I don't entirely blame her, as my mother with anxiety, depression, PTSD and BPD got worse when she started meds.
Can you try the validation tools like SET? Is your H open to physical exertion or exercise? That might help. This lock down certainly makes things hard on so many levels...
Edit: it's good that he may agree with BPD, but neither of you are professionals. I'd back away some from the BPD angle when discussing it with him, but rather focus and how you can work together. This is your safe place to discuss the BPD angle
