Melania was used in a political attack ad by Cruz people first, implying something tawdry about her, and Trump always counterpunches. Think of it as he was defending his wife's honor. Seems politicians are allowed that, aren't they?
@aligncareI have heard the source for that as being from other than Cruz,but even if it WAS Cruz,what's the big deal? She WAS a professional model,and Trump was well aware of the photos being taken when they were taken because at least some of them were taken aboard his private jet. Instead of embarrassing Trump,he most likely got semi-wood over all the other men he thinks will envy him because he bought a hot wife.
Remember,Trump is one of the most shallow fools on the planet. His whole sense of self comes from swimming in the illusions that HE is "Mega Man" and all the other men are jealous of him. In truth,she is just an expensive bauble,like so many other things with his name on him. The ONLY person he cares anything about in the whole world is himself,and his mini-mes,and he only cares about them because he sees them as reflections on him.