I would like to assist you with your question.
Can you give me a few more details so that I can provide the best possible response?
How long have the two of you been dating? Can you explain what it is about her...or the relationship...that leaves you feeling insecure? A few examples would help.
Have you dated much? Please tell me a little about your dating history.
Insecurity in a relationship can come with many things...how the two of you communicate, experiences with past relationships, and certainly your experiences with your parents, siblings, and friends.
I see that you are offline right now. When you come online I will be notified and we can chat about your situation.