Hello:
I don't know what you mean by "natural way to avoid pregnancy." There is a very complex and labor-intensive way to chart your vaginal temperature in order to determine whether you're ovulating; however, this is not a very effective means due to the fact that it requires specialized equipment, calendar, a very regular cycle and a very big time commitment. And even if you follow all the protocol, there's still no guarantee you won't get pregnant.
You also stated that you don't think condoms are "safe." I don't know what you mean by "safe"; however, it's important to know that when used properly, condoms can prevent both pregnancy and infection. I think you owe it to yourself to get better educated about contraception and risk reduction. I suggest you begin with these pages on MedHelp:
birth control and contraception
http://www.medhelp.org/forums/Birth-Control-Contraception-/show/382
risk reduction:
http://www.medhelp.org/medical-information/show/1723/Safe-sex-
condoms:
http://www.medhelp.org/medical-information/show/2255/Condoms