after max broke up with sid, alexis, a 'friend' of sid, broke the cardinal rule and started dating max less than a week after the break up
in regards to friendship, the cardinal rule is never dating your friend's ex-boyfriend
"after max broke up with sid, alexis, a 'friend' of sid, broke the cardinal rule and started dating max less than a week after the break up" What is the definition of "cardinal rule"?