It's absolute bullshit that women get any of the man's money when a divorce happens, but if you sign a prenuptial agreement, there's really nothing she can do, no matter how good of a lawyer she has. And since Cena is rich, it's not like he can't hire some great lawyers himself.
I don't see how this could hurt Cena's public image, though. Divorces happen, and since he signed a prenup, how is he in the wrong? Everyone will know that she's the gold digger. If Austin hitting his wife wouldn't hurt his image, then neither will Cena getting a divorce.