Sex while on the bc pill

So, my boyfriend and I normally use a condom along with the pill, but he wants to try it without since I'm on the pill. How effective is the pill on it's own? Should I be worried if he does cum inside me? I've been taking the pill for over a year and I've had no problems with it, I'm just nervous about it because Im in collage and a baby is not on the list at the moment if you know what I mean!