Withdrawal

A few months ago, I just lost my virginity. Actually, I really do not want to give it to him because I want to keep virgin 'til I get married, but he insists that he would take full responsibility on me. Now, we've been having sex for three months now and I'm still nervous everytime we do it. We're not using any condom nor birth control pills, but he withdraws and pulls out his dick as he cums out. I just wanna ask if it's safe? Will you not get pregnant even if your guy withdraws outside you?