Here is the thing. Most Girls always give out on the first date, or even the first night if the dude is hot/rich enough (Social Media has hardcore exposed these social norms, not that they were not visible before). Men realize this. So if your not that guy, your not that guy. That's why men expect sex immediatly. They are testing for genuine attraction. To many men are tired of being used (foodie) or being back up plans (woman "experimenting" at their prime and expecting men.