i say go for it.
running into the guy is almost the best part, because you know youre pounding his girlfriend, and that he may have possibly tasted your semen during a hello kiss, but you arent really sure if he knows or not.
then, when he finds out, its even better, cause, say, youre like, at a drift event, there is a sweet tension that lingers in the air, that just makes everything a little better.
for you that is.
it totally sucks for the other guy.