Overall purpose is to show the true character of the man underneath. This man is always helping his wife but more out of effect then sincere wish, he wants to be seen a sympathetic, modern man who believe in equality of the sexes. He however is a racist underneath, who would not tolerate a interracial marriage, and would not have married his wife whom he claims to love, if she had been black instead of white. We all hide behind masks, and generally how we behave at certain times somethings let slip those masks to show what we truly are underneath. It could be a weak man, standing up for himself against a bully, to show strength of character, or a selfish man who would do anything to make a quick buck, using other people misfortunes, by sweet talking to them. So I guess he is just try to show that we all wear masks to hide the ugliness inside us that we would rather others not see, but it however comes through at some time or another.