Navigating My Open Relationship's Boundaries...

I'm thirty-six and have been in an open relationship with my partner for a little over a year now. We both agreed it would be okay to explore outside of our core connection, as long as we communicated about everything openly and honestly... I've always felt a certain pull towards dominance play, but never really acted on it with anyone, until last week... My girlfriend (who's also in her thirties) is very much into giving pleasure and being the recipient of care. She finds it incredibly intimate when I'm gentle or romantic during our time together... So this weekend, a new guy I've been chatting with showed up at my house, and we agreed to take things further without any cameras on for once... We didn't exchange names, but he was really into control dynamics, his kind of thing. We were clear that it was roleplay only and nothing like real dominance... But as the night went on, I found myself stepping in more than just roleplaying it. I don't want to get too specific about what happened since this is a public forum, but suffice it to say we both got into it pretty deep... Here's the thing, my partner knows I like the idea of being dominated, and she even tries to make me feel that way at times... But actually taking control in a real way was surprising. It wasn't just about pleasing myself or exploring desire; it felt like a whole different dynamic with someone outside our primary relationship... And now here's my big question: Am I the asshole for not fully communicating beforehand what I might do when we started this experiment? I mean, we both knew it could go beyond casual roleplay, but did I have a responsibility to be more explicit about taking charge rather than just letting things evolve? What would you guys do in my shoes? How much does someone's sexual comfort zone dictate what they can and should say ahead of time in an open relationship like ours?