First of all, you need to take a pregnancy test and find out if you are.
If you love him, you wouldn't keep this from him. He deserves to know the entire truth before he makes a big decision like joining the military. It's not right for you to make the decision for him that he should go on ahead with that decision while you raise his baby. It's also not right for you to expect your parents to raise your child, instead of asking HIM to help.
I'm not saying these things to be mean. There's just no room for secrets in a successful relationship. I'm sure he understood as well as you that unprotected sex can lead to pregnancy. If he was concerned about his future, he should have used a condom. As it stands, it looks like a baby might be in his future. It's not up to you to keep that from him.
Take a test. If you're pregnant, please tell him. If you're not, stop having unprotected sex with him if you don't think he needs a child in his life right now.