Am I normal for feeling jealous?

Recently on a vacation, the female I'm dating, (we are in our 30s) said out of all her former high school classmates, she wouldn't mind seeing a particular guy she liked who is now married and said "she was out of his league." I was appalled and said, I really had no interest in seeing old love interests as my only interest is in her. Am I wrong to feel this way? Insecurity?