That prenup she signed must be ironclad, bulletproof and would boot her out into the streets buck nekkid if she violated any of its conditions for her to put up with what Trump has been torturing her with.
If past divorced female employees are any indication, yup - the prenup and accompanying NDA is all probably pretty solid. Trump has admitted that he is ok providing for an ex, but they have obligations in order to maintain that support, i.e. not dishing on any abuse, his baby carrot penis, lack of intelligence or morals, business stuff, etc.
I think it is more likely she is protecting her connection to wealth and her parents (who live in the States now). The desire to stay wealthy in America as opposed to not wealthy in Slovenia is strong, like 'ignore the husband who can't spell your name raw dogging porn stars' strong.