Open Relationship Challenges

I’ve been in an open relationship for a few months now, and it’s not as easy as I thought. Last night at work, this guy who comes in often flirted with me again. There was something about his smile and the way he talked to me that made my heart race like it hasn’t in forever. We kissed goodbye when he left, and I couldn’t stop thinking about him for hours afterward. My partner knows our agreement includes emotional connections too, but is it wrong of me to feel this strongly? Is it normal for things to still be so intense with someone new when you’re already committed elsewhere?