Dear Clint,
i’m in similar situation and all i can say is that insecurity is only related to how do you feel about you.
When you see her talking with other boys, maybe you feel you’re not good enough or so interesting and funny compared to her friends.
Maybe what affects you is the idea that she’s kind to other guys too.
First of all, talk to her about how you feel. Than, when you start feel that way, try to understand the real reasons why do you feel that way.
Maybe your jealous is only fear or insecurity of losing her. Remember, a relationship is about two individuals that trust and love each other. I hope that I have helped in some way! (Sorry about the english, it’s not my native language)

Best Regards,
Di