In my opinion, there should not be any formal sorry and thanks between the life partners. Both of them will have a common life. If one is suffering, the other will also suffer. A person is having two hands. A cart is having two bullocks. Similarly, a family will depend on the wife and husband. So there should not be any formalities. Each should understand the other, adjust themselves and should go on together. When the wife is angry, the husband should be silent and when the husband is angry the wife should be silent. Then things will go smooth in the family and no necessity for sorry or thanks will come in the family.
If the wife has done something well instead of saying thanks to her if you reciprocate to her in a similar way she will be very happy. Of course, some people these days are accustomed to say these two wards in all circumstances and these words are losing their importance.