I think you'll know.

A condom has broke on me once and when it broke it hit my guy's member and he almost started crying. Lol you can feel it snap and usually hear it aswell.

Your just worried!

It could be the condom aswell, maybe he uses the type thats thin, the kind that your not supposed to feel.

I'm the guy!

When you put it on make sure you pinch tip of condom to get air out cause that can sometimes be the cause of popping. As for feeling it, not always. It can even sometimes slip off and not know it. As for how common, well you might want to post that on a guys forum cause who better to ask!!!

Good luck!!

It happened to me and I didnt realise but my boyfriend did. And if it happens you would know cos it wouldnt be a little hole unless someones tampered with it .... You'd know...