My Client's Secret Fantasy Came True

I've been in an open relationship for about two years now. My partner and I have a mutual understanding that we both can explore with others, as long as it doesn't interfere too much with our shared life together. A few months ago, one of my gym clients, Alex (in his mid-thirties), mentioned during a session that he had this fantasy about working out under the supervision of an attractive fitness instructor who would push him hard and make him sweat in more ways than just physical exertion. Initially, I was taken aback. But as someone with my own personal boundaries set for these types of interactions at work, I saw it more as a challenge rather than a dealbreaker. We talked about the logistics and what this fantasy would entail, nothing that would cross any legal or ethical lines but definitely an exploration beyond professional behavior. Last weekend, we decided to make it happen in a private studio space after hours. Alex and I both agreed on certain limits beforehand, mainly mutual consent for all actions, no physical touching except encouragement pats when appropriate, and clear communication throughout the session about what felt good and didn't cross lines. It was exhilarating and intense. We stuck to our rules, and even though there were moments that got heated in a way we hadn’t anticipated, both of us left feeling satisfied and excited by this mutual exploration.