Has anybody been in a relationship with someone who has a child? I am in such a relationship for the first time and to be quite honest it has made me grow as a person. (No they haven't put me in a torture contraption and stretched me)

Let me say that I am a very strong, self confident person, who now has started feeling jealousy over a nine year old girl. Is this normal? O.K. maybe I shouldn't use the word normal with me in mind. Let me know what you think...
THANKS