Why do men feel that they must buy expensive commodities for a woman if they want her to stick around?

It's ridiculous. I know that men can see that I'm not a gold digger--so why must they impress me with money? Yes, I want all of those material goods, but not from a man that I'm not even serious with. I don't get why they are so overbearing with their money. I want to know about their heart, not their wallet. They are only inviting me to use them. Then later they accuse me, when I never even wanted anything from them. Why do they do it?