When you only bestow money and sex on the girl, don't expect her to give you more than that.
I've talked with many western guys and they admitted that more often than not when they are looking for a girlfriend, the first thing they see is physical beauty rather than inner qualities.
Since guys are born to be surpercial, don't blame girls for the same defect.
Actually when you think you're looking for love, the first thing you see is still physical appearance. So it's as hard as impossible for people to look under the surface. Only when you are old and experienced enough frustrations can you understand what keeps a relationship going.