I am also not a lawyer, but I seriously doubt a court would accept "I didn't expect to actually have to live up to my end of the deal!" to be a valid change in circumstances. By this logic almost anyone could back out of a long term contract: "I didn't expect to still be in business 24 years later when I gave you that 25 year warranty!"
To quote the top few results I got searching online for "law of frustration":
> However, frustration of contract is not acceptable in all circumstances nor in all types of contracts. It is acceptable when the law finds it unfair to force a party to comply with the contract terms ___due to events that are outside of or beyond their control___.
To quote the top few results I got searching online for "law of frustration":
https://en.wikipedia.org/wiki/Frustration_in_English_law
> it is "not lightly to be invoked to relieve contracting parties of the normal consequences of imprudent bargains"
https://www.law.cornell.edu/wex/frustration_of_purpose
> when a later and unforeseen event impedes the buyer's purpose for entering into the contract
https://www.upcounsel.com/frustration-of-contract-definition (emphasis mine)
> However, frustration of contract is not acceptable in all circumstances nor in all types of contracts. It is acceptable when the law finds it unfair to force a party to comply with the contract terms ___due to events that are outside of or beyond their control___.