Safe Sex

As I am with my first ever partner and I am his first ever partner to ever do anything remotely sexual, I know I'm 99% safe from any STI's. Meaning we don't HAVE to use condoms to pretect against them, but that doesn't mean you shouldn't. We still use them during my period, for obvious reasons, and on days when they're nearby and there's no reason not to be extra safe for pregnancy protection (as we are both 18 and 19 and in college, with no plans of having children yet). Please share your standing on the subject. Have any of you had STI scares? Or a with some who does have an STI? If you don't have an exclusive partner right now but still have sex, how do you deal in those situations. I'd really like to know. Thank you for sharing ahead of time.