HOW DO I PERVENT IT???

I was with this guy and he told me he wouldn't wait anymore. I told him I wouldn't had sex until I get married but st times I feel bad because I feel like I'm making him suffer because I could of tell how much he really wanted it at times but I stuff strongly believe that if he waited for do long already he could of waited awhile longer.I wanted to but I'm just very scared about getting pregnant because I just started college and I'm very focus in my major.