I think tough love is in order here, like snodderly suggested. Just my opinion. But enough is enough of her cake-eating!!!

Do what your gut tells ya, your the one that has to live with your decision. What ever decision you make will be right for YOU!!!

Also, I have been learning that anytime your faced with a tough decision to stop and really think about it in depth before you react(some suggest days-weeks-months). Then, when the time is right, the decision you make will be well thought out and something you can live with for the rest of your life with out guilt.
TIPPER