Tips Please!!

My boyfriend and I are pretty sexually active, I track my safe days and we don't ever do it on my unsafe (green) days. We have gone unprotected, but only for a little while and them immediately put on a condom, he doesn't ejaculate. I know it probably sounds stupid, but I'm super worried all the time about getting pregnant! We do our best to be safe, and I just want any tips you guys have about making sure I stay NOT knocked up, anything I should know about ovulation and fertility and my chances of getting pregnant from precum. Thanks ❤️