Please make sure to use a condom. And by the way, it’s not just the
that can give you nasty diseases: The condom-free penetration even without
ming is already a big risk.
Just some of the things you can get by having unprotected sex include:
- HIV
- Genital herpes
- Syphilis
- Hepatitis B & Hepatits C
- Chlamydia
- Gonorrhea
- HPV (which can cause anal and throat cancer)
Your question about the safety of letting someone
inside of you reveals you have apparently not informed yourself about safer sex and the health risks of sexual intercourse yet.
PrEP teatment, as mentioned by kwhotboi does not protect you from anything but HIV.
Please inform yourself further, for example at the website of the CDC:
http://anon.projectarchive.net/?http://www.cdc.gov/msmhealth/STD.htm