there are a lot of problems in Mexico due the drug cartels indeed but am from Mexico City and i can tell you that personally i havent seen any problems,just some things on the news, but from what i know the worst places are Tamaulipas, Monterrey and a few others. if the problems are really bad i cant tell you, what i can tell you its that at least in Mexico City you can have a good time go to the concert and being fine. i mean we all know that Mexico its not the most secure place but that doesnt mean that you will get robbed or kiddnaped just for coming a few days. but well i think you should put your wifes and your safety first so dont do anything you dont feel comfortable doing.
Exactly , MExico City was one of the most dangerous places in the country , now is one of the more secure , now the cities that was the paceful cities are the dangerous , like Metallica says , Sad But true