Can you get an STD if your partner isn’t infected?

I ask this because for example, insulin doesn’t work unless it is injected directly into the blood stream, not taken orally.

I was just thinking,
if two people were infected with the same STD, could they be together without making the STD worse?

me and my gf have been goin out for a year and were 15. weve been having oral for a while and she was my first real girlfrined that id done stuff with and same goes for her. therefore we were both never previously infected with anything casue it was our first time. so wat im asking is can i get an std from having oral with her and only her if we both arent infected?
also just to be safe what type of condom should i use?

I was wondering if it is possible/ likely to get a sexually transmitted disease in your eye if infected semen got into it For example is it possible to get herpes type 1 or 2 in your eye by getting semen in it and not actually touching a herpes lesion. Is it possible to get genital warts/ hpv from semen and not direct contact with a wart? What other stds can be spread, and are they treatable? Any bit of information helps.

Do you think society is getting what it deserves?

can you give me percentage chances of catching a STD especially AIDS with an infected partner?and what are the chances if you do it with a condom?also are some positions or techniques helpful in reducing the chances of catching an infection?

Please help me, i am 15 years old boy, and i never had sex before, one day i was studying biology,i was reading about Syphillis and the symptoms i read are happening to me, i am not exactly sure but i think so, like it says there will be an infection on the penis and it will heal by itself, and it did. It says there will be pain on joint areas. and i feel some pain in that area. That is why i think i am infected. I never had sex before and i never wore other people’s underware but i masturbate often, is there any other way i might be infected by syphillis. PLease help me. PLease