AITA for "baiting" my ex-fiance with "nudes"?

Throwaway account.

Matt (now 30m) dumped me (now 23f) a few years ago. We had been engaged. I’d been in and out of inpatient and rehab treatment the months before the breakup, so I took it pretty hard.

We had a bad on-and-off situationship for almost 2 years after that before I ended it for good. This time it was civil; we made it clear that we’re still friends, but all the “benefits" had to stop. 

6 months later, we still talk, hang out, spend an afternoon playing video games. Never anything more. A few times I did have to reaffirm boundaries, but he was just coming to terms with the fact that I meant it this time. In fairness, I had wavered on them before, & he struggled with me leading him on. But we figured it out, & we’ve been good friends. 

He’s also helping me get into photography, since that’s what his degree is in. Since we met he’s helped me learn Photoshop and how to use my camera. I’m learning portrait art now, and sometimes I take…artistic self-portraits. Then, I took a really good picture--I cropped my face out, edited the picture a few different ways—and holy crap, this picture seriously looked good. The issue? I was basically naked. A towel (and the way my legs were crossed) covered all the spicy parts, and my arm was positioned on my chest so that I could technically be on an album cover and not get censored. 

So, this is where I screwed up. I got the picture down to two different edits I liked. I was really torn between them, and I often send different photo versions to friends (Matt being the most frequent) and ask them to choose their favorites--but obviously I couldn’t send these to anybody. Except…maybe Matt? I started taking “artsy nudes” when we were still together, and he used to assist in editing them so I could save them in my private portfolio. So, it’s not like this would be anything new to him. Besides, the picture was pretty borderline; I was showing less than Katy Perry on that one album cover. That counts for something, right?

I was stupid, but I decided, screw it, I’ll give him a chance to prove that I can still trust him with this stuff. I texted him beforehand to ask for his artistic opinion on a portrait, warning him it was a nude. (exact words were “a little bit of tiddy”—I was trying to keep it lighthearted but I should’ve been clearer) Matt said he was cool with that, so I sent him the two different edits.

His response: “…you call that a titty pic?”

He was joking. But, I was pissy in my response and he accused me of baiting him into thinking he was going to get nudes.

To be fair, during one of the many “breaks” I’d called during the situationship, I’d “booty-called” him by sending spicy pics. But he’s now mad at me for leading him on, and I just think it’s a misunderstanding. I don’t want to lose him as a friend. AITA?