It's hurtful to steal from your girlfriend.
Donald is really hungry, and doesn't have much money, he's embarrassed to tell his girlfriend this though, and notices her purse.
Donald wants money for food.
Donald asks his girlfriend for some money for lunch, stating that he's a little broke at the moment.
Donald puts his hand into his girlfriend's purse and takes the money.
The girlfriend scolds him for not telling her sooner, and grabs him the money.
Donald's girlfriend comes out, catching him, and instantly breaks up with him.