Proper Condom Use?

Me and my boyfriend of a year and a half recently started having sex. I am not on any hormonal contraceptives, so we have been using condoms.

I don’t have sex during ovulation, we use the condom properly from start to finish, and I don’t let him ejaculate inside me, even with the condom on.

Despite all of these provisions, I am still beyond petrified of getting pregnant. We are both students and I am not ready at all.

I don’t want to go on birth control because of all of the mental health effects, as I am currently going through some gastrointestinal issues and don’t want to combine medicines.

Is it safe enough? Should we go celibate?