A question about South East Asian customs. Details inside.

I live in a college town with a very diverse ethnic population and while at the grocery store this morning (in Texas) I observed the following: As I was entering there was a man and woman of what I believe was S.E Asian descent and who were between the ages of 60 and 70 also entered the store. The man went to the door and waited while his wife got a cart.
After she got the cart the man took off at a very brisk pace with his wife following behind pushing the cart. He went to the produce section where he chose some vegetables and put them in the cart. Then he took off to the next display, again at a brisk pace, while his wife followed along with the cart at a slower pace. When she reached him he put the vegetable in and again took off.
I encountered them off and on throughout the store and this was the same pattern. He would get something, wait for her to catch up, put it in the cart and then take off again. I never observed any input from her about what was purchased she simply pushed the cart to him and he put in what was in his hand. The whole time I saw them he never touched the cart and she never touched the products on the shelf.
They were to the checkout line in front me and when the time came the man loaded the groceries from the cart to the cash register conveyor while his wife looked on from the back of the cart. He spoke to the cashier in very heavily accented English.
When the groceries were sacked and loaded back into the cart, the man paid for them and then his wife then stepped aside from the basket and he took to pushing the cart out with her following.
My first thought was that because of the groceries, the cart was more of a burden for his wife but she was the one who pushed it throughout the store and to the register in the first place so perhaps it was something else.
Why did it seem like the man wanted nothing to do with the basket of groceries until it was paid for? Why did she seem to have so little interest in what was purchase? Had she already had her input before they got into the store? Is such action or behavior common in Asian cultures?
I am not faulting it or questioning the way it was done, only noting it was different from what I am used to seeing. Here in our town if you see a man and woman in the grocery store he is usually pushing the basket and she is selecting the groceries and at checkout time it is a toss up as to who pulls out the card.
I am just trying to learn a little more.