You can only get out of the contract if--1) There is a clause or provision in the contract allowing you to cancel, and you comply with any of the terms or requirements of that clause; or2) The buyer breaches (violates) the contract in a material (important) way, such as by not being able to close.Otherwise, the change in your life circumstances is completely irrelevant: contracts are enforceable even if it would be better for one of the parties to get out of the contract. If you refuse to sell, the buyer can sue you and seek a court order compelling the sale (called seeking "specific performance" of the contract), and/or seek what might be significant monetary compensation (called "damages") from you.