Spermicidal condoms increase HIV transmission risk. Their only proper use is for contraception, not STD/HIV protection. However, any increae in transmission risk is minor compared with the exposure itself, so this makes no difference in my advice above. But for maximum protection in the future, use condoms without spermicide.
Welcome to the HIV forum.
Please get in the habit of asking about HIV status before sex, not afterward! In my opinion, you had no business having sex with someone whose HIV status you didn't know -- and sharing your own status as well.In the long run, exchanging HIV status before sex (and avoiding sex or at least being extremely careful about condoms etc with partners who are positive, don't know, or give vague replies) is just important for gay men's avoiding HIV as consistent condom use for anal sex.
OK, lecture over. But I make the effort to repeat it every chance I get.
I cannot judge exactly when the condom broke. It sounds logical it happened with the snapping sound, but you're in a much better position to know than I am.
There are no definitive, official guidelines when to use PEP, and local guidelines vary from place to place. Given the apparent brevity of the unprotected exposure, the chance of HIV transmission, even if your partner is infected, is very low. However, if he turns out to be HIV positive, you should visit a local provider who understands HIV prevention and is experienced with PEP, and who knows local guidelines, then follow his or her advice. If your partner says he is HIV negative (and has been tested fairly recently), I see no need for PEP. If you never hear back from your partner, PEP might be warranted -- but again, the decision should be made with a provider on the scene, not a distant forum like this one.
You probably know that the effectiveness of PEP depends on starting ASAP after the exposure, preferably within 24 hours and for sure within 3 days. Whatever you do, act quickly.
Good luck-- HHH, MD
also, I am not sure if the condom was spermicidal or not.