It is the way he tells her to sit next to Phil at the end of her forced speech and she practically runs out of the room. He repeats himself to her and the aides, because maybe she did not hear him (you know, being stupid, foreign, and a woman) and she still refuses to sit down in front of him in the audience.
He quickly comes up with a joke and the audience laugh at her expense. Obviously it is small potatoes in terms of news, but what a chilling window into their lives. The body language is just awful - she is constantly leaning away from him and he summons her up to the podium like a dog. Those who think it staged clearly have a better opinion of Donald's and Melania's acting talents than I do.
There was a great observation up thread about how the most bigoted men have foreign wives. It clearly comes from a place of deep hatred and misogyny. They see women/foreigners as inherently inferior and are looking to have that constant feeling of superiority in a relationship because their fragile egos cannot handle being with an equal. They are monumentally insecure because they suspect, rather correctly, that they are deficient in their humanity. In order to forget about that deficiency and mask their own self-doubt and self-loathing, they choose a partner in whose eyes they can always see themselves loom at least twice their normal size. Part of it is making your wife financially dependant on you. Banks and Trump own their wives (through the vast difference in their personal wealth), Farage employs his.
Those who do not feel sorry for Melania fail to appreciate that money is no consolation when it is an instrument of control and you do not own any of it. You don't know that at the point of embarking on a new relationship, whatever your motivation. I am relieved for her and her son that she does not have to live with him.