Burst into tears during a scene and am struggling to understand myself. Please help!

I'm fairly new to this stuff and so is my partner, we are just figuring it out as we go along but are trying to stay informed and safe. Last night we had some particularly intense (for us!) degredation going on, he was berating me for not being able to climax easily and was speaking like it was conditional to him being there, and like I was being ungrateful for him showing up to service me and not even climaxing etc etc and I just burst into tears. He immediately stopped and proceeded to pull off the most tender aftercare I've ever seen from him, but I didn't even see it coming at all. I didn't even have time to process it and think to use the safe word, it just hit me all at once.

I struggle to orgasm with a partner and it takes me a long, long time. It was never something that I'd been self conscious or upset about before, but there was something in me that made me really feel like I was defunct or inadequate. It morphed into feeling like real rejection from him somehow. It was like my logic was being completely overridden because I know that's silly, but in the moment it felt like "yes, yet another reason I'm not good enough, and it's all my fault, I deserve what is happening to me"

We spent a long time doing aftercare things and talking it over. He was very good at pulling me out of that space and comforting me afterwards. But now I am sort of scared of myself because I feel like I understand myself and my boundaries/triggers a little less now.

I often ask him to degrade me about things I am genuinely self conscious about, because it feels cathartic that he sees it in full and still loves me anyway. But this was unexpected because I don't really think about it much, and don't generally view it as "points docked" if that makes sense. I don't know what else might trigger this reaction in me and want to know how and why it happened. Can anyone help me understand?

I suppose I will add that I am processing a lot of traumatic stuff in therapy and have been for a while now, but none of is related to this specific issue (besides it morphing in my mind into some unforgivable flaw I have the power to fix but don't, which makes me deserve terrible things that come my way)