Plenty of married people have a celebrity hall pass the one person their spouse would allow them to cheat with given the chance but when you are a celebrity, the rule gets tricky. Case in point: Jennifer Aniston, 46, who told hubby Justin Theroux, 44, that her biggest Hollywood crush is Jon Hamm… and is now in talks to star with him in a movie! Justin’s a good sport and laughs it off, but deep down he’s starting to get bent out of shape, says a source close to the couple. He trusts Jen but worries that Jon is a player. Sounds like Justin’s been watching too much Mad Men!