More on sex with other people

Did I mention that D is attached? Has another relationship, one that started way prior to our meeting? Or that he's slept with tons of people (but not since we've been together)?
We were walking and talking yesterday and we started discussing my interest in sleeping with more people.
"It's not that I want another committed relationship," I said. "It's that I'm super-curious. I want to figure out how I can have fall in love right now and not have it be meaningless no strings attached sex--but not have it be a big relationship--I don't have the bandwidth for one of those."
D laughed. "Well, it's something we could do together. I can take you to some play parties, maybe some swinger parties, and you can see what you like and what you might want to do more of."
"Sure," I say, and I like that idea, but I am also thinking "Hmmn, what might I want to explore without D (as opposed to with), and how do I make that happen without screwing this relationship up (literally)?
"You know, when I met you, I was so into you and so into making this work, I couldn't consider sleeping with anyone else except you (and Z, my original partner), but now, after all these months, my curiousity is coming back."
"I'm good with that," D says, "I just don't want you to run off with someone else. I worry you will meet someone you like better."
"You never know," I say, enjoying the moment, but also aware this is a good moment to process carefully.

(Inspired by a comment by Cherrie, the senuous libertine and a woman after my own heart)