However the thing about being a Stepford wife, is that she can't be blackmailed. The only thing Trump has on her to demean her - if she ever decides to spill the beans - is her dodgy immigration status in her first year in the USA. Compared to what she will know about him, which will fill volumes, that's nothing. How far would he go to silence her if she decided to jump ship?
Typically a narcissist will demean and devalue someone publicly when they are no longer of use to him. So I could imagine that Trump might demean her by making unpleasant comments in public about her plastic surgery, her sanity, her menopausal status, even reactivate John Miller personas to malign her from a distance. Narcissist typically spread rumours vigorously as part of character assassination of their enemies, to destroy their credibility. He would possibly impugn her mothering skills and/or try to use their son as a bargaining chip for her silence.
Any or all of that could possibly happen, though whether it will, who knows. But when or if she no longer serves his purposes, the man child is likely to show his true colours in a sharper clearer light. She is safe from attack as long as she chooses to stay in Stepford mode, but not safe from his embarassing behaviour with women, and that might tip the scales eventually. Men as narcissistic as Trump typically stay womanisers throughout their lives, they like the rush of power it gives them. She probably saw her need to tolerate that as part of their bargain in the beginning, but she could change her mind, and may be changing it now.