My girlfriend is on the verge of breaking up with me. What can I do to save my relationship?

[Jaime]

I'm sorry to tell you this but you need to grow some balls!!

The way I see it, it's too late, you are too dependable and she already saw that.
You were not prepared for that relationship and you need to accept the outcome, you will get over it, eventually it will benefit you as long as you are willing to make some changes.

That crazy jealousy you have over past flings she had is correlated to your insecurities.

You need to focus on your career, you really do because it really surprises me your lack of insecurity for someone in the Army to be an officer who already has a career which means you already went through college, you should have learned through experience in college or even at school!

The best action I think you should do is to talk to her and recognize to her the mistakes you have made, finally letting her go. It's going to happen wether you like or not so it's better if is your decision(which it really isn't ) at least you will be prepared for it.