Melania seem to be very uncomfortable on the political stage and I'm not so sure that she agrees with what Trump is spewing. After all, he has attacked women in general and now she has to stand next to him. She doesn't smile or applaud a lot. She's his 'trophy' wife and she knows it. That in itself is very humiliating.
He collects "things". He uses them. He abuses them. He discards them when he tires of them or after they serve his purpose.
Melania looks like a batter wife. Not physically battered, but in other ways.