I thought of that, and I'm sure it's true with Marta. But the guy was a dirt-poor radio DJ for the first three. I'm going to stick with 'they had nothing bad to say about him.' I guess a lot of people part ways especially those with no kids, with no hard feelings.
His first wife obviously doesn’t talk to the press about him or we’d be hearing from her at least monthly for a while, second wife went with him to NYC when he started his national program, divorced him about two years later. So she might well have agreed to silence in exchange for a heftier settlement.
Of course I just thought of another possibility. If they are both remarried each may not want to disrupt her present marriage by talking about her prior one.
I do not wish to imply that Rush has something to hide, but you know the media sharks would love to have someone to say anything about his personal life that could be twisted by skillful editing into something negative. And people unskilled in media relations are sitting ducks for those types, as Rush would know.