When my ex had announced his departure already, I had several months to prepare. Grocery prices mysteriously inflated by $25 or so, carefully balanced against what savings I'd managed because I knew he never checked receipts. Got myself quite a number of groceries on him in the months following (gift cards, to be clear).

for anyone else following along, a great way to stockpile for the Great escape should you ever have to make one is taking 10 or $20 in cash at the grocery store every time you use the debit card. "cash back?" yes, please!!