i am going to assume you wash your hands on a regular basis. or at least, i will assume you have washed your hands since you broke up with that other girl.
so what are your chances of infecting your new girl with something your hand acquired from your ex? slim, but you could go wash your hands with soap and warm water for 20 seconds right now.
the STD i'm thinking of specifically is syphilis. it's transmitted by skin-to-skin contact. the syph bacteria dig into the skin and cause large, painless but gaping sores called chancres. do you see any gaping sores on your hands? people tend to notice their hands. so if you had a chancre on your hand, you'd probably have seen it and wondered, "what the hell is that?!?!"
otherwise, handwashing takes care of so much of the other things that can cause genital infections. hands are so dirty in general andit shouldn't surprise you that a lot of folks just don't wash like they should.
want to do safer manual sex? wash your hands and wear latex gloves (like the kind your dentist wears). then use water-based lube.
LA County STD Hotline 1.800.758.0880
Toll free STD and clinic information, and condoms sent to your door for Los Angeles County residents.
1 in 3 sexually active people will be exposed to a STD by the time they turn 24.