Exploring Boundaries in a Non-Monogamous Setup

I’ve been in an open relationship for about six months now, with both of us fully committed to exploring various kinds of connections. My partner and I agreed early on that all activities would be discussed beforehand and consented to by everyone involved. Last week, my primary partner introduced me to someone new at a mutual friend’s party. We ended up in a bedroom alone, both of us very attracted but cautious due to the setup we’ve established. After several minutes of intense kissing, I found myself on top, straddling him as he was lying down. The sensation of his fingers pressing into my hips and guiding me was exhilarating. He then flipped me onto my back; his body felt so warm against mine. We continued making out passionately until I felt the tip of his penis pressing against my entrance. With a nod from both of us, we proceeded to have fully penetrative sex, which was incredibly intimate given the circumstances and our agreement to only go this far with each other in an open setup. The act itself was extremely pleasurable, as he thrust deeply into me repeatedly, making sure to maintain eye contact and check in verbally about our comfort level throughout. It was a moment of intense connection despite being part of a non-traditional arrangement.