condoms do prevent some but not all stds. herpes can be transmitted from skin to skin contact. anal sex can cause tiny tears in the lining of the rectum or anus and make you more prone to infection. i suspect you will be fine since the condom was intact and you appear to have been careful. having "anonymous" sex with anyone is risky however since you do not know if he is hiv positive or has an std.
chance of std from protected anal sex. i had anonymous anal sex with a man and i am worried that i've caught something. my penis never touched anything besides his hand while unprotected. i penetrated him with a condom on after that and he didn't penetrate me. just wondering what kind of risk i've put myself in. seriously kicking myself.