Pre-nuptial agreements and alimony: how is the pre-nup handled if you move to another state?

So my SO and I are going to do a pre-nup. I want to avoid having to pay unreasonable amounts of alimony, since it's highly likely I will be making more money than her. Her salary is good, but mine will be better. I know several states won't allow a pre-nuptial agreement to modify alimony payments. My question is: what happens if the pre-nup. is drawn up in one state, but then you move to a state where some of the pre-nup. is rendered invalid? Specifically, a state that doesn't allow the pre-nup. to modify the terms of alimony payments.

Any advice would be appreciated.