Wow just WOW...

I would just stop making any of your money allowed into her hands . Too bad her credit card is not your problem!... Buy food for your children and yourself ..If she sits down to eat .. ask her to go into another room and explain to her you were only able to buy enough food for him and the children.. Let her get mad ... she gets mad about everything anyway.

I would tell her unless she starts to contribute to finacially to the house hold you will have no other option that to divorce her, Plain and simple .

Children should always come first !

Im sorry your in this hellish situation but children always comes first , no matter what !