ah please explain then, im literally uneducated in this regard. why might it be passul?
I'm not a mumche, but I can try.
If a get is not given willingly, it is invalid. If the pre-nup says that the husband has to pay $x a week until he gives the get that is likely considered "forced"
The RCA pre-nup trys to avoid that issue by saying that he has to pay that sum until he comes to beis din. There are rabonim who say that halachikly it's a distinction without a difference.