Should my boyfriend and I not be sexual together?

We are in our early twenties and just started having sex. I decided to stop doing anything sexual with him and we haven't done anything sexual for a week and a half. We don't want to have any pregnancy possibilities and I feel strongly that God is telling me not to be sexually immoral. However, I know it's hard to stay celibate. My beliefs tell me to be 100% pure. How can I stop myself from wanting to do sexual stuff?