Probably not the pan in you, jealousy is fluid regardless of sexuality! Some people get jealous just from their partners talking to others and some people wouldn't even get jealous if their partners flirted or kissed other people!
That's why setting boundaries and having open communication is good for relationships because people's thoughts and feelings on a matter can differ so much!

maybe it's the pansexual in me, but I'll never understand ppl who get jealous when their crush/significant other is "close" (or more like assumed to be) to someone just because they're the opposite gender and imagine a convoluted scenario in which they're lovers, just because they don't outwardly hate each other