Hi Sara,
As others have said, the husband/boyfriend (doesn't matter whether they are from an eastern or western culture) should always attempt to pay (at the very least). It shows the respect your husband/boyfriend has for his girlfriend/wife and gives them face.
As for travelling the world on $3000, unfortunately that won't work. In many other forums you will see how hard it is. The problem is getting the visitor's visa. Many countries require chinese citizens to get a visitor's visa before they can enter. But to get that visa, you have to show that country that you will return back to China after entering the country. That is the hard part.
$3000 will give you the chance to visit one country depending on which country it is. Many will not require that much, but it is the minimum someone should have before they go visit another country.
David: $50 a day for food... depends on where you go. In Asia, that will get you a few days of food...at least for me it would...but that's why I like to eat where the locals eat (like hawker centres).... the food is generally better there.