Since some guys still don't understand how girlfriends work, let me offer some ground rules around food and drink.

If you buy her something to eat or drink; it is hers.

If you buy yourself something to eat or drink; you let her have some.

If she buys herself something to eat or drink; it is hers.

If she buys you something to eat or drink; you let her have some.

Such is the way of the world.