Its interesting that a lot of these threads have "my man has never had this problem, but..." responses. Let's try to acknowledge the pink elephant in the room. This happens to men a lot. Funny too where someone mentioned the "if an ultra-hot chick doesn't get you hard there's something wrong with you" tack. I am fairly sure this is either from a woman who has no understanding of the problem or a guy who doesn't swing or otherwise attempt to sexually perform under "duress". Many of these "frustrated" female halves who have to tolerance for limp dick are perpetuating the very problem they are frustrated about. Make no mistake. Even though its fun to think of guys as sex machines that can get turned on at the drop of a panty, there is a lot that can sabotage a woodrow, and it has nothing to do with desire or attraction. Short of a direct intervention (injection, pump, etc) the only way to hope for a positive outcome is to make the problem appear to not be a problem. Clearly sometimes lack of penile cooperation is due to lack of desire, but more often then not the problem arises because he really REALLY wants to fuck you silly! Relieve the pressure and you'll be surprised the results.
As for the question of stopping or not to address the problem, that's a situational thing. The other suggestion if it works for you might be of you find yourself unable to go due to distractions (wife getting her world rocked) perhaps give up and cheer them on. When they're done then it is your turn! This way you're not thinking about what the others are doing cuz they already done it!
And when all else fails, make sure your oral skills are top notch!
Mr P