Wife has a problem with her diet. Whilst going through my wifes hand bag the other day i found a?

packet of toffees. I took this as a betrayal as i had put her on a diet as she is way too fat. She has not even tried to lose weight, and is still huge, she tries to say that it is because she had the twins a month ago and other lame excuses, what should i say to her.......i really can't divorce her as it is her jobs that keep the money coming in, me being unemployed an all!