Lindy Loo, that's a very compassionate answer.
justawife, I would second other peoples' suggestions that you look into counseling. Since your parents had problems with fidelity, I think a lot of this is about them, and therapy would help you separate your fears based on your parents' mischief, and real issues in your relationship.
Also, since you got married so young, and your husband is so much older than you, I wonder whether there is a big power differential in your relationship, and you are having trouble with him looking at other women because that's a way for you to have some power. And I also wonder what is going on for your husband - i.e., why a 37 year old would have married a child of 15, and whether there is something to your concern that has to do with an addiction to very young women.
All these are just speculations; I may be way off. But your situation seems to me to have a lot of different facets, and therapy would really help you sort out the issues with someone who is trained to help you do that.
Best of luck to you.