CW: abandonment, divorce, gaslighting?

...maybe it's BPD?

Long story short: therapy for \~30y, trauma in childhood but CBT/DBT has helped, never diagnosed. Last year, my husband of 12 years left me for a coworker, and his parting thoughts after I reacted predictably (I was pretty normally upset) were "Have you ever considered you might have BPD?" 

My mother is diagnosed, so to say that this was heartbreaking is an understatement. It felt like he was weaponizing my trauma and years of therapy in a very intimate and cruel fashion. But now I can't stop second-guessing myself. Doesn't matter what my therapist or current partner says, I dwell on that like Joe Biden himself called me up and personally confirmed that I have it. Just to clear it up, my ex is NOT a therapist.

I know this subreddit isn't for diagnosis, and that's not what I'm asking for, but has anyone ever experienced this type of diagnostic gaslighting before? I find myself worrying now that I've convinced all my therapists that I don't have it and that because someone who lived with me for over \~3.5k days is in a clearer and smarter place to better assess me than a detached professional.

In truth I don't know what separates me from someone with BPD, beyond the official diagnosis, and I feel guilty and ashamed at the idea that I've been swindling professionals and am "not making progress" as a result.