What's so is, you got triggered. From here (a safe distance away), that's no biggie: we all have our triggers, you're a lot more up-front about yours than I typically am about mine, and I admire you for it. It's also quite a compliment to your bf and the relationship you have with him that you'd even risk getting triggered the way you did. Sure, you couldn't predict for sure what would trigger you -- but you were willing to take the risk, you didn't respond with your customary "No under any circumstances" to him as you had with everybody else. He sounds kinda special to me.

If you'll pardon me for pointing this out, though: what you're adding to simply having been triggered, seems to be making it a lot harder on you:
I'd recommend setting all that other stuff that you're adding aside, and just looking (from as close as you dare at the moment) at whatever came up for you when you got triggered. My take on it is that that's what's up for you to deal with ("process", as I like to call it), and looking stable and together for your bf is something of a luxury and a distraction.

That said, I do think it'll create more room for you to go through what you need to go through, if you can get your bf to see that it's really not about him, that he's not bad and wrong for having suggested whatever it was that turned out to trigger you, and (this might take some getting used to) that he did you a backhanded favor by (innocently, not maliciously) bringing up something that was there for you asking to be worked on anyway.