Legal Question in Family Law in Virginia

I doubt such an agreement could be enforceable even if it were in writing

and signed "by the parties to be charged", The provision "that we would cohabitate until we could agree on a way to get out of underwater mortgage" seems nebulous and might well be interpreted as "never"and therefore not reasonably performable by either party within a reasonable timeframe and thus rendering the contract invalid and unenforceable (my opinion).