Went Full Roleplay Without Consent From My Partner

So, I kind of went a bit rogue in bed last night. It all started back when I was in grad school, and the stress got to me so bad that my partner decided to spice things up with some role-playing. I loved it! But then we moved on from school to actual jobs and other adult stuff. My partner isn't really into kinks anymore, saying they prefer a more straightforward approach to sex now. Fair enough, right? Or maybe I'm the asshole here for not respecting their limits? Anyway, last night was just one of those nights where everything seemed to be closing in on me and I needed an escape. So instead of asking my partner if we could revisit some old roleplay, I kind of...went ahead with it. I mean, I did tell them about the fantasy I had during foreplay, but it wasn't exactly a serious offer or anything, just talking things out as we usually do before getting intimate. But then, without saying much more, I started acting like an old professor grading papers they handed in for class. And while this might sound ridiculous to anyone else who hasn't been there, I found myself getting really turned on by the whole thing. My partner was a bit taken aback at first but seemed to warm up to it eventually. They let me continue and even joined in when I asked them to take on another role too. Afterwards, we talked about it again, and while they didn't seem upset per se, there was this awkwardness that made me feel pretty guilty for not respecting their wishes more explicitly beforehand. I'm trying hard not to read into anything, but the question is, am I really the asshole here? Was my assumption of mutual understanding overstepping what we had agreed on earlier? So yeah, venting about how grad school stress got the better of me yet again in an unconventional way that ended up surprising both of us. Maybe I'll learn to communicate more clearly next time, huh?