Relatives and friends say that wealth is getting better every year after marriage, buying a house and buying a car. Why do they all say that my wife brings me wealth?

This is due to human's inertial analytical thinking.

People are good at finding reasons from results, but unfortunately they only believe what they see.

You bought a car and a house through your own efforts, but they didn't see your efforts, only that it was after you got married. So they will attribute the reason why you bought a car and a house to the change of your wealth after marriage.

And the last factor after marriage is your wife.

Of course, this is also related to the feng shui habits in different regions.