Add fuel to the fire

 *** Add Fuel to the Fire

"I would like to do something to help, but I don't want to add fuel to the fire."

Imagine that you saw a friend of yours that is married kissing another woman. This woman is your wife's best friend . When you get back home  your wife is offering a cup of tea to your friend and his wife. So , during the conversation your wife says: " Sabrina has just called me saying that she is coming to visit us. She has good news to tell us.  I invited your friend and his wife to join us for dinner" . You look at your friend trying to slip him a note but he didn't realize that Sabrina is the girl he was kissing.  You call him privately and advert him about the danger. Your friend says: " We would love to know Sabrina but we better call it a day". Your wife replies adding fuel to the fire: " You already know Sabrina but your wife doesn't " 

In Brazil this expression goes like this: Colocar lenha na fogueira.