Is prenuptial agreement still valid if one party does not adhere to terms? (Revised w/correction.)

A pre-nuptual agreement is a contract, and as such it must be supported by consideration to be valid.  "Consideration" is a legal term of art that basically means something of value.  In other words, for a valid contract to be formed, there must be consideration.  No consideration.  No contract. That's a bit of a stretch, because more than likely there was consideration of other kinds going both ways. The position Spouse 2 would have to take to invalidate the contract is that Spouse 1's agreement to provide the life insurance policy was an essential term of the contract and that Spouse 2 would not have entered into the agreement without it. Who represents the deceased spouse in this context?  That would be whomever stands to gain or lose depending upon whether the pre-nuptual agreement is upheld or not.