If i've had sex with a person who has an std does that mean i have it to?

Maybe: Any time you are in contact with a person infected with any germ there is a possibility that germ can pass to you & cause infection.There are important variables.Barrier agents like condoms can reduce the chance a germ will pass & infect.Some STD's have intervals where they are not contagious.Some only pass during certain forms of contact. If you think you may, get checked. They can make U sterile