that's a horrible thing to say and i would never say something like that about my husband to his face or behind his back.
she obviously has no respect for you as her husband, and she obviously doesn't mind putting you down in front of everyone and humiliating you.
turn the tables around on her and see how she likes it! ((don't do that, don't put yourself on her level))
just let her know how you feel and let her know you won't put up with being treated that way in front of anyone.. let her know that if she loved you she wouldn't degrade you, no matter what the situation.
hope this helps!