So confused. Having unprotected sex but not getting pregnant

Me and my boyfriend have unprotected sex sometimes and at first I got a bit paranoid about it all , but now we do it a lot but he doesn't cum inside of me, I'm just thinking about pre cum? Like I don't want to be pregnant im just surprised with my odds because we literally do it so much? Is it because ovulation matters. But then again we have done it a few times during ovulation unprotected