Like others have said your question isn't very clear. It depends if she goes back because she is missing home or you are getting a divorce or separating.
If she goes back only to visit for a few weeks or a month I would think it's your moral duty to provide her with food if her family cannot feed her while she is there.
But if she goes back because the marriage has ended and she is suing you for divorce then the subject is different. If you get married in the UK you need to look at your own laws...
Here is the answer that Mr Guzman gave Bob not too long ago.
http://www.dr1.com/forums/464923-post13.html